Squat: you may be dipping with your knees forward, instead of dipping with your hips and pushing the knees out. Also, you may be loosening your back up abit in the hole. The shift in momentum can be rough for most people.
Bench: The shoulder issue may be that you are able to tighten one side of your back more than the other. I have had traiing partners with this same problem. One way you can see is when you bench, have your spotter pay attention to how you are laying. Often times you will see a twist in the body, because one side is tighter than the other. Scapular retractions could help alot. Along with some rehab type shoulder work, incase theres just a drastic imbalance. I would recommend more but five weeks out is not the time to change too much up