What can be wrong with my shoulder?

This is a follow-up from a previous post, if you want more detail.

I injured my shoulder in 2011 falling down some stairs. I suspect I dislocated it but it popped back into socket right away so I didn't seek treatment. I had still experienced a lot of pain and have ever since experienced minor occasional pain in my shoulder blade I assume is from that.

Last week or the week before, I was pushed, almost punched in the chest right on the border of my shoulder at a concert. It was hard enough to knock the wind out of me. It was sore for a few days in the same achy way my shoulder had hurt the last 8 years so I suspected it just irritated an old injury. It was probably a 3/10 pain-wise.

A few days following the hit, in the same exact spot, my son's head hit me while he flailed in protest like toddlers do. The pain was instantly EXCRUCIATING. I couldn't even inhale, it hurt to just think. The pain radiated from my chest down to my finger tips. After a little bit, I could move it again but the pain was an 8/10. I couldn't sleep well for the next few days. I got an X-ray done shortly after posting my first question, and it isn't dislocated or anything. The X-ray was a dead end. The pain had subsided some, though with the loss of pain I gained a loss in mobility.

I made an appointment with an orthopedic surgeon but that isn't until September 9th. I'd say it's back at an 8/10. I'll add more detail in an answer.