Hi i have had costocondritus type pain over the last week that has gone but now i feel as though i have a fist in the middle of my back like a winded?

Back pain: May be reflux could try ranitidine and see if helps. Reflux may be associated with gastritis which can be related to H pylori infection so need f/u . Is it right or left? if right could be gallbladder, Are you coughing? may be bronchitis infection or even pneumonia. ( costochondritis is at times associated w/ mycoplasma bug )Rarely especially at your age could be cardiac F/u/ w/ doc