Problem with right hand. Kind of thing.

I used to regularly go to the gym Two years back , while doing bar dips, i had a kind of jerk and due to which i couldn't lift my right hand. There was no pain at all, just that i couldn't lift even a pound with my right hand. My trainer advised me to take rest . Eventually my hand became normal. So after a year i went to gym again, and after lifting the weight for some time, is I started experiencing tje same thing, my right hand became weaker than the left. I counsulted few doctors but none of them knew what exactly is the problem. What i noticed: When i do biceps exercise, i feel my biceps muscles are less involved as the right bicep is less pumped than right one and i feel as if i am using shoulder muscles to lift the weight. After exercise, i feel less of my right arm as compared to left arm and my ring finger and pinky finger feel less to me as compared to others. Also i feel good when i squeeze my forearm. There is no pain at all Just the weakness kind of thing.