While lifting weights for overhead shoulder press, one of the dumbells came all the way up while the other one reached only midway. The spotter let go of the one arm that was straight and tried helping with the other one due to which the arm that was straight locked out and all the pressure came on the shoulder joint I felt some slight ripping feeling in my shoulder and I let go of the weights. Now as far as the ROM is concerned I can do circumduction and extension addiction and however it's just the shoulder flexion where I can't hold my arm straight above parallel for long or hold my arm overhead for long. Kindly advise me as to what it could be and what can Indo regarding this. It's not hurting when I move my arm as mentioned earlier only te flexion part hurts. I am a certified personal trainer (if that helps). So you can use relatively complex terminology as you don't have to mellow it down for me. Thanks in advance.