I have a 2004 chevy Malibu ls and my rear back tires is trim inward but the rear driver side is worse . took tire off and control arm is band a little and iits hanging down need help please.

Ok I think your spindle bushings in the rear are broken the squealing is from the tire rubbing against either the strut or rear control arm with the car on the ground look at the wheel to see if it A ) is leaning in on top from the rear of the vehicle B) turning inwards from either the front or the back the spindle has a front/rear bushing on it C) or the rear control arms have a bad bushing or are bent did you hit anything or drive off a curb or slide into an object in the rain like a curb then this is it look at the tire for wear marks it will point you to the possible contact points D) the rear wheel bearing/hub may be loose or shot causing the wheel to lean inwards E )the rear strut on that side has failed making the body dip down as well as the stabilizer link and the tire is contacting the spring seat or the inner fender F) also there is rear wheel alignment settings that are out from all described above but if you drive normal and it has stock tires on it then it's a bushing or arm that's doing it you must go to the rear and feel for excessive heat on the tires so you know which or both wheels to check

if the wear is on the inside of the tread ---wheel bearings , failed suspension bush,arm
if it is on the outside of the tire tread ,-- bent lower control arm
if it is patchy around the tire ---failed shocky
it is appears as if the tread is feathered towards one side of the tread--- wheel alignment
Tack it to an accredited suspension specialist shop for a proper examination and a rear wheel alignment

Here's a long answer. It could be 100 things. But if your wobble is showing up at low speeds, look at the tread on the tires. Does it snake back and forth? If so you have a belt separation in the tire. If it's not a tire, you may have a suspension part that's bad. Or, more than one. Control arms, ball joints, tie rods, (inner and outer), bushings, and wheel bearings, and any one of them could be waiting to send you into the ditch, or worse. Many garages will give you a free check of your major components. Try them. If you can't or won't, jack up your truck so one wheel is in the air, grab the front tire with one hand at 9 o'clock and the other at 3 o'clock. Wiggle the tire. A very little play, is probably ok, but if you have more than 1 inch of movement, you probably have a bad wheel bearing or a ball joint or control arm. Now grab the tire from top and bottom. Try to move the tire up or down. You should have NO play, at all. Any movement is bad, probably a ball joint, but it still could be a bearing. When you're driving, if your steering wheel is wobbling side to side, it's a front wheel problem. If you just feel the wobble in your seat, it's a rear wheel problem. Don't let the problem keep getting worse. If you put used tires on, it's probably a tire. That, you can fix. Anything else I've mentioned, you can't fix without some very expensive tools, and an alignment machine. Good luck.

Does the mustang have independent (IRS) axel or the solid 8.8 rear axel?

the door tag says 30 PSI, with your tires i would suggest about 32 or 33 psi because they have a very soft sidewall.

replace the strut tower as the rubber shock is warn out

Your back strut is bent

Had a similar problem with a different car. Rear struts / spings were worn. Caused rear to sag enough to push wheels out and wear out inside portion of tires.

Yes you should get it align, in the long run it will cost less than new tires.

That's known as negative camber (positive camber would be if the top of the tire were leaning outward). This should be able to be fixed with an alignment as long as the suspension isn't damaged (ie, a bent control arm due to an accident or a hard hit on a curb, pothole, etc).