Right shoulder pain/locking out during overhead press

[LiftingFood]

Mark, before I begin, let me berate myself before you berate me.

I'm an arrogant son of a bitch that disregards injuries. People call me an asshole, but I don't give a fuck because I squat. Also, I curl for the girls.

Anyways, whilst I'm overhead pressing (current weight 115 lb., yes it's light weight for all you strong kids), I notice after the 3rd or 4th rep while I'm pushing the bar up right pass my ears, my right shoulder begins to lock out. In other words, I feel like as if my shoulder is locking out more and more as I get closer to the top of the press. Sometimes, I can't fully perform a fully locked out OP because of my fucking shoulder. My left one is fine, only my right is bothering me. I haven't experienced any problems for bench press either.

Do you have any idea what's wrong? BTW, I don't have anything to record a video of my form.

[Mark Rippetoe]

I'm an arrogant son of a bitch.

I'll be the judge of that. You have a shoulder injury. It must be diagnosed. I can't do that from here. Let me know.

[LiftingFood]

I'll be the judge of that. You have a shoulder injury. It must be diagnosed. I can't do that from here. Let me know.

Yes, but now is the time I must stop being arrogant. I was doing seated dumbbell presses today and felt absolutely no pain/locking in my shoulder. I don't have the money to diagnose anything for myself right now. Should I just not even barbell press for a while and continue with seated dumbbell presses?

[Mark Rippetoe]

Try standing DB presses next time and tell me how they feel.