I have long sitting hours which is causing my shoulders to bend and is leading to myback in a bending position. Please suggest some easy exercises?

Try McKenzie Therapy. Look up mckenzie therapy on the internet. There are many sites that can give you useful information. The exercises should help. They are most effective when taught by a credentialled therapist.
Ergonomics. Get up each half hour and walk and stretch.( esp. Your neck and shoulders).If u sit @ a computer most of the day change the position that your forearms and hands reach the keyboard ( or mouse etc).