Pulled Trap?

[Douche_Nutz]

Today I was climbing a gate about 6 feet tall and i was pushing myself up because I had nothing to grip with my feet and I felt a pain in my left trap. It was a slight pain, nothing huge. It hurt when I tried to do pullups/chinups, it hurt when I was pulling down the bar for the final part of pull-downs. I could do rows but when I did dumbell rows on my right side and used my left arm to hold me up on the bench it hurt like a bitch.

I tried picking up a 25 lb weight with my left arm and shrugging it but there wasn't any pain.

Any idea what it could be?

I'm hoping for some similar experiences or something because this probably wouldn't be easy to diagnose.