Bench Shirt Issues

Hello everyone.
I’ve been training for about 2 years, wanted to enter a meet but couldn’t find any clubs that would sign me(it’s required in my country in order to participate).
About 2 1/2 months ago I found a club with a really good trainer and found out that in our federation there’s no separate category for raw and equipped, and being faced with the risk of having to go against equipped guys as a raw powerlifter my trainer suggested I try equipment.
And so I did, the squat suit was a pain but the moment I put on the bench shirt I knew I had ran into trouble. Anyway, we finished a couple wourkouts and he gave me some gear (I got a super centurion size 42 and a size 44 super katana A/S, I’m 185 pounds so the shirt is quite loose) to try and learn to use it.( the thing is I have to train alone most of the time since my trainer is like 200 miles away and it’s a pain to go there weekly, and when I get there I’m tired as hell from the drive)
Anyway, long story short, I managed to get accustomed to my squat suit in a little over a month and am now at 95-98% success rate on squats with about 60-80 pounds added.
The thing is I’m having great trouble touching in the shirt. My raw max bench is about 265, and while 335 is quite easy to press, I can only lower it to about 2 inches off the chest. If I try to row it down to my chest or put more weight on just to get the touch, I get some pain in my left shoulder that radiates through my arm up to my elbow(it’s quite a stingy pain, not dull or anything).
Because powerlifting is not well known around here, I’m simply limited to asking either my trainer or on forums. I’ll go train with him this week, but I figured I could ask here for some opinions as to why my shoulder hurts. I have thought that since it’s more difficult to pinch my shoulderblades together since the shirt pulls them forward, that my shoulderblades lose tension and as I get closer to touching my shoulder moves with the shirt, but through filming myself I could not find any obvious evidence. Also, my grip is about 3-4 inches wider than I use for raw.
So, if anyone has experienced this before or has any ideea what could be the cause of shoulder pain during shirted bench(ironically, the shirt protects the shoulder if used right, and I am completely aware it’s a technical flaw), then your help would be greatly appreciated, since I’d like to get some opinions from more than a person.
Thanks a lot!

I don’t know anything about benching in a shirt but I have had similar issues with shoulder pain. In my case, I figured out that it had to do with weak rotator cuff muscles, the rotator cuff is supposed to stabilize the head of the humerus but if it can’t function properly it can result in compressed nerves and other tissues causing a lot of pain. The solution for that is to do lots of external rotation work, meaning rows and chin ups as well as stuff like band pull aparts or rear delt flys. All that stuff should also help you keep your shoulder blades together, which is just as likely to be causing pain as the rotator cuff itself.

Thanks for the input! I have thought about this and while normally I do some external rotation, mainly as warmup and lots of back exercises, recently I’ve been neglecting them because the meet is closing in and I’m trying to focus on specificity.
I imagined it could be a nerve being compressed by either lousy form or by the shirt itself since after I take it off in about 10 minutes there’s barely any pain.
Thanks again, I appreciate it.