Will exercise help to change pectus excavatum ?... if yes may i know what exercises to be done sir?

Not typically: Pectins excavating is a deformity of the chest wall that involves the bone structures of the ribs and sternum. As such, exercise will typically have little or no effect in a typical case, consider being seen for an exam and studies to give you more accurate info based upon your individual case.

Pectus excavatum: Pectus excavatum can be surgically repaired, but surgery is usually reserved for people who have moderate to severe signs and symptoms. People who have mild signs and symptoms may be helped by physical therapy. Certain exercises can improve posture and increase the degree to which the chest can expand. http://www.mayoclinic.org/diseases-conditions/pectus-excavatum/basics/treatment/con-20028599