shoulder injury

Hello,i hurt my shoulder doing a loose interpretation of the Eagle pose from yoga(sensored://static-p3.fotolia.com/jpg/00/05/93/94/400_F_5939494_v6BjtM32jQktrr4P45QTzMjIlaclhPpT.jpg) if the link is not good for you, it involves intertwining the arms with the upperarms roughly perpindicular to the body, and the forearms vertical and the palms are facing eachother. anyway, pulling across with my left arm on top I hurt my left shoulder somehow. not too severely but enough to be noticable. this was about 10 years ago.as little as 4 years ago, I couldnt do bench press without aggrevating it. as little as 3 years ago I couldnt do shoulder presss. I haven’t done weight training since. anyway, my shoulder always feels sore if I have to walk any real distance with a book bag on which is relativy infrequent.
It is also more sore becuase I have started training a martial art, and on occasion it may be sore, but I just started the training so I don’t know what makes it sore exactly.anyway, I got some advice on another forum for some exercises for this and another injury. the other one was a knee one and the advice worked great. the shoulder one required aparatuses I didn’t have at that time. So my hope is that somebody can help advise me on some exercise I can do to restore my shoulder without using any equipment such as weights, resistance bands, etc. Thank youbrandon