AC Joint Sore To Touch After Incline Bench Press

18 days ago I was doing heavy incline bench press and I had this subtle onset of discomfort in my right shoulder. I suspect it to be my AC joint because it has been sore to the touch and initially for the first two days my range of motion in front of my body was limited (arms overhead didn’t hurt but getting them about halfway up did, maybe 2/10 on the pain scale). The range of motion came back after two or three days. As of right now I have no pain, complete range of motion with the exception of placing my hands behind me in a bench dip position & my AC joint is SLIGHTLY sore to the touch. My shoulder also feels kinda weak and unstable. I’ve tried researching it and it seems to me like a grade 1 AC sprain, but I have not been to the doctor yet. Anyone ever had an experience like this?

What type of warm up are you doing?