My needle is not movin up or down..switched to zig zag and it moved left and right but no up and down..Im lost without it..whats wrong and how do i fix it? Bernina 1090 s

Really not able to provide much help without knowing the make & model. However, if it is an older mechanical machine, quite possibly it is seizing due to old oil that has dried.

Wheel on right side that controls the needle up and down is very tight...

The stitch Width selection regulates straight-stitch or zig-zag width. Needle position does not determine straight or zig-zag. Needle position just determines whether the needle's home position is center, left, or right. Needle position can be used with straight or zig-zag stitching.

There is a lever for positioning the needle bar. When you move the lever to the left middle or right , the needle bar too should follow the same. Try to do that. If it doesn't follow the lever and stays at one end, that means the machine needs to be oiled. Not like most sewing machines Supernova swings the bottom rod too to left and right when Zig Zag is engaged. I recommend to spray some WD 40 first, to inside of top and bottom side of the machine , and later to apply machine oil to every moving joints.

could be something wrong with the cam that does the zig zag stitch

Look at the knob which creates the zig-zag stitch (1-4) at the top right of your 930. In the center of that is a silver knob that rotates right and left. That silver switch moves the needle position right and left.

Hmmm sounds like an issue I had/have with a singer stylist. There is a knuckle part that connects the zig zag mechanism to the needle bar. Mine had a pin that kept slipping out. When I took it apart (and lost the pin) I also discovered that the "round" holes the pin went into were work out and were more like ovals. The machine is now a parts machine.

yes, it's very possible that the control/knob needs to be replaced
or the cam or gear that works the zigzag

Did you switch the metal plate to one of the ones that won't allow left/right movement by any chance?
If the wrong plate it in -The machine somehow figures out that the plate won't allow the needle to move in the left/right directions and only does a straight stitch or funky other stitches.

THis problem occurred as I was sewing on Neoprene. I was using Gutterman all-purpose thread and a size 80 needle. Tried switching to a size 70, then to size 90. Still unable to zig zag. After inserting a test sample of cotton, the zig zag worked perfectly, so I knew it was not a mecahnical problem. I switched needles again. This time to size 90 for stretch fabric. Voila! Problem solved.

Because it is almost a straight stitch but the needle continues to move in a zig zag fashion is reason to believe it is in a long stitch. By changing the number of stitches per inch there will be a very noticeable looking zig zag stitch.