When i was 19 (now 23) while performing a dumbbell press with 70 pound dumbbells, i lost control of my right arm causing a dumbbell to strike me in my chest. Ever since, I've had an irritating cracking sensation around the sternum. Have gone to chiropractors for readjustments and yet the cracking still occurs causing me to have to maneuver in certain ways to find relief. Led to believe it is probably scar tissue left from the injury. Can anyone give any insight on what possibly is wrong, or what can be done to relieve this cracking? Thanks