ExRx.net

wide grip, over grip, under grip, and side grips which one is better for u and do they all work different parts of the back im assuming yes

yes they all work slightly different muscles! Do them all, alternate between work outs! Do you have a particular weak spot? Mines my Rear Delts so I use a wide grip palms away mostly but throw in a close grips palms facing now and then to give my bi ceps a bit extra! If you do have a weak spot use the grip that hits it the best!

wide grip is my weakness, close grip palms to me are my best.

Wide grip pullups involve shoulder adduction, while close grip pullups involve shoulder extension. The rear deltoid is a synergist in shoulder extension but not in shoulder adduction. Otherwise, the same muscles are involved in both movements, though at different angles.

For most people, extension is a stronger movement than adduction

The pronated (palms away) grip puts the biceps at a mechanical disadvantage in flexing the elbow, while a supinated (palms facing) grip puts them at an advantage. A neutral (palms facing each other) grip, some allege, is the best grip for training all of the elbow flexor muscles.

Recently I've been doing supinated (palms to me) pull-ups to help with my lagging biceps, but when I switch types in a few weeks I'll change to wide-grip palms away.