I do not have enough hot water from my shower head. I have plenty of hot water in my bathroom and kitchen sink. What can I do to remedy the problem?

Shower heads have flow limiters installed in them. This means the water heater cannot sense the water flowing and therefore it wont come on. Take the shower head off and look in the end for a piece of plastic that is in the swivel. Remove it. Then put the shower head back on.

If you are using water in another part of the house most times the pressure at the bathroom shower will go low. For instance if some one in the kitchen draws water in the kitchen sink this will make the shower water even turn cooler because of low pressure. Flushing the toilet will also do the same.
Most houses are plumbed with half inch water pipe and would work a lot better if it was three quarter inch to give more water pressure.

Comes off the top of the water heater and is routed to the bathroom sink, the kitchen sink, the shower/tub, outside shower and washing machine (if equipped).

Where it suddenly became not hot enough, it's probably not an adjustment. It sounds like the stem needs to be replaced

The issue is the flow sensor, if the faucets are restricted (like showers heads) then there is not enough flow to trip the sensor. This could also be related to pipe size and water pressure.

You need to have the flow switch looked at. The low flow of the water to the lavs and the kitchen sink, they all have as small demand next to t bath or shower,
Tom

it sounds like 1(or more) of the motorised valves arent working.find the valve and make sure you are getting power to it via a tester,if so then it probably needs the head on the motorised valve changed

The cartridge in your shower faucet will probably need replacing

Auto/self adjusting anti-scald feature in shower body and /or flow meter defective/cloged.