Suggest Remedy For Pulled Muscle And Pain In Ribs

Hey, I was stretching in the mirror and ihad my right arm stretched up high and all of a sudden when i got into the shower i felt a really tight feeling right below my Right Nipple and now its like flat almost looks pushed inward a little bit compared to my left side but it also feels like there is no muscle between my rib bones under my right nipple compared to my left side, i have no pain and its not tender to touch im wondering maybe I pulled a muscle or maybe dislocated one of the ribs right below my right nipple Im 5'10 145lbs soim pretty skinny so i can see my ribs to me it feels like maybe my muscle got stretched but dont understand how that could cause it to be very flat and going inward a little bit the indentation is probly the same size as a quarter it doesnt go inward very far at all that i can notice maybe a few Centimeters hopefully can get any advice