I've made some good gains on my flat bench in recent months, up until i injured something in my left shoulder, on or after a day where i was pushing my PR to about 200lbs, just 1 set at 5reps. It doesn't hurt when resting, but it hurts a lot when benching, even just doing push ups, not OHP though.
After the injury i struggled to even just maintain the weight over about 1 month, even now it isn't completely healed. It's invisible though, i have no idea what was actually damaged in there. Now that it is more or less healed, im scared to increase the weight once again because i don't know what really caused it in the first place. What do you do about this? What to look for when trying to make sure that the current weight is "safe" so it can be increased without risk? Is it a lack of warming up or stretching?