right shouder in sling for 6 weks torn rotat cuff ned help
i fight at 145 i walked around at 155 160 i do boxing and jiu jitsu and mui tai i'm 18 years old i'm 5'8 i tore my shoulder 3 months ago i'm now 142 they just now want to do surgery doc dont want me doing activies for a couple of months but i have to stay in shape in the mean time like should i run n lift just with my left arm is there any exercises i should do to help or anything at all to keep my muscles toned routines watever u no weight gainer n lift with my legs instead of upper body need help from sumone who no's what there talkin about

ps rember my main goals are to not lose any more weight and gain weight bak keep muscles toned n not get less in shapethink it also be better to lift with my left hand since i'm right handed it will make my left hand that much stronger so any excersises weight routines and running routines to make me gain weight bak keep muscles toned and keep my stamina or any thing possible to help