Four months ago I was at my peak of lifting (weight wise). One day while doing shoulders, I needed 80lb dumbells for seated shoulder press. Gym didn't have em. I went to 85. Ultimately, my arm gave out and I didn't drop the weight so my arm was jerked to the ground and I fucked up my arm between my shoulder and bicep. It hurt. I had residual pain for a couple weeks and it was just generally sore....two months later, I come back and, well everything is the same in terms of strength, but there are certain things that just produce a twinge or uncomfort in that area..
Ultimately, I went from 250lbs to 180 and now I'm back in the 200s (moving, being broke, the injury)..and now I need to know what direction to go in..

Typically, I run for 30 (3mi, 300 calories, interval on the elliptical) then I do whatever lifting routine for the day that I can do. The problem is I'm hesitant, I am afraid of fucking up my shoulder completely, so I feel Im becoming lax. I don't know if I should just start doing more cardio or if I should just throw caution to the wind essentially and keep going up in weight. Although my boyfriend has just joined the gym I have no one to spot which makes me hesitant of the later...

Idk, I guess I'm asking how to reformat my routine so that I'm not utterly fucking bored while at the same time not risking my shoulder.