07 hhr rear tires wearing bad on inside

Springs are sagging or suspension is bent. Could be worn bushings causing components to be out of position. Springs support the weight and the shocks dampen the bounce so he doesnt keep bouncing- if it does then you need shocks. The sagging indicates something else is wrong.

can be anything have a 4 wheel alignment done ---problem for excessive tire wear --out of balance --improper tire for vehicle -chamber to much/to little- air under / over inflated -abuse -bad shock/strut-bad hub/axle --suspension alignment / worn /damaged

Your car needs a Rear Wheel Alignment, the components need to be inspected/checked for wear and then aligned. Worn ball joints, wheel bearings and so forth can cause bad alignment & tire wear.
Also it's hard to get an accurate alignment once a tire is worn on the inside or outside of the tread.

if you don`t rotate the tires this can cause abnormal tire wear.but with tire wear on the outer 1/2 of the tire indicates either the camber setting is off or you could have bad rear springs changing the ride height of the car causing the change in camber.to find out you would have to have a 4 wheel alignment done to check rear alignment readings.if the springs are worn then the ride height can be checked with a tape measure and compared to specs,if off then the springs should be changed along with the rear shocks.

Does the vehicle rock faster at higher speeds, or is it a constant no matter how fast you're going? Is it a gentle rock, or does it seem like more of a shake at higher speeds? Does your vehicle have hydraulic shocks, air shocks or regular shocks and springs?
If your vehicle is rocking at low speeds and the rock turns into a shake or vibration at higher speeds, you might have a bent axle. For this problem to be bad enough to fees as a rocking motion at low speeds you should probably be able to tell by looking at your wheels -- if your axle is bent, you should see that one of the wheels seems tilted slightly. If you move your car a few feet and look again, it should look like it is tilted in a different direction. If this is the case, have the axle replaced ASAP to avoid more damage to your suspension system.
If the rocking does not change at any speed, then you have to consider your suspension system. If you have a hydraulic or air suspension on your vehicle, it might be malfunctioning. If you have air shocks, one of the air bags that holds your vehicle in the correct position could have a slow leak -- this could cause that part of the suspension to float down as it loses pressure and back up as the pump adds more air -- which would feel like a slow rock inside the car. The same could happen with a leaking hydraulic. If this is the case, bring the vehicle in to a mechanic and have your suspension checked ASAP to avoid causing more damage to the system.
If neither of these is the case your wheels might be out of alignment. This would also cause a funny, cyclical noise from your tires as you drive and should be taken care of ASAP as it will cause extreme wear on your tires. If this is the case, your tires will probably already show uneven wear on the tread (if the inside of the tread (near the center of the car) is worn out more than the outside of the tread then this could indicate a bad alignment).
If your tires are not worn funny, and nothing else here has helped, you might have bad tie rod ends, ball joints or loose lug nuts on one of your wheels. First, make sure the lug nuts on each tire are properly tightened -- if there were loose nuts you might have fixed it. If all of the nuts are tight, jack up your front end so your tires (one at a time) is about an inch off the ground. Grab the top and bottom of the tire and try to rock the wheel -- if the top and bottom of the wheel move towards the center of the car, you probably have bad ball joints and you should have these replaced IMMEDIATELY (they are a vital part of your steering system and need to be in good shape for safe driving). If the wheel does not rock up and down, try grabbing the tire on the front and back and see if it rocks (if you have only 1 tire off the ground there should be no play ... if both front tires are in the air then pay attention to the tire on the other side of the car as you do this or have someone hold the steering wheel). If the tire moves, without turning the steering system of the car (the other tire doesn't move with it) then it's likely to be your tie rods or tie-rod ends. These are also a vital part of the steering system of your vehicle and should be replaced IMMEDIATELY to ensure safe driving.
If none of these are the problem. take the vehicle to a mechanic and tell him what you have done to check the vehicle (this can save time by helping the mechanic eliminate possible causes).

Wearing on the inside can be caused by an excessive camber angle or excessive toe out, or both. Either of these can be caused by worn or damaged suspension parts. Camber affects Caster, and Camber and Caster affect Toe. Toe affects the Thrust Angle. (These are the major suspension angles involved in wheel alignment) The "dishing" or "cupping" is caused by what is sometimes called "wheel-hop" this can be caused by worn-out struts or shocks and can also be caused by tires that are seriously out of balance.

The recommended "Fix" would be to inspect the ENTIRE suspension system to check for loose and/or worn and/or damaged parts. Replace any of these parts as necessary. Then replace and balance the tires and head straight over to the alignment shop to have all of your suspension angles set to manufacturer's specifications. (Most tire stores also have an alignment machine)

I shouldn't think an 07 model would have enough wear on the front suspension components to cause the type of problems you describe, unless you sustained damage in an accident or drive in rough terrain. I would suspect one or more bad tires or misalignment. Worn struts could be part of the problem. If the shudder you describe is in the front end, rotate your tires front to back and see if the shudder moves to the rear. If it does, then it's most likely bad tires.

TAKE VECHICLE TO WHEEL ALIGNMENT CENTER.SOUND LIKE VECHICLE OUT OF LINE.COULD HAVE BAD WORN REAR WHEEL BEARING.

well uneven wear is not the bearings ,the main cause is worn shock absorbers ,wheel bearings will just make a noise

Yes a worn out or broken shock will cause tire wear. But most likely you have a suspension problem. Need to check for play in upper & lower ball joints & inner & outer tirods.