Hi Hope this message finds you in good health. I have gone through your complaints and understand your concern. I generally see many cases like this at my clinic.I give them a splint,rest,analgesics,anti-inflammatory tablets and ice pack till the swelling reduces to some extent. Then i get an xray and if necessary an mri done .Nothing to worry about. pain under ribs can be generally caused due to many reasons like pleurisy,neuritic pain,fibromyositis etc it seems when the 1st time u sneezed,it might have inflammed some part of soft tissues in that area. if this episode is incompletely treated first off,then such symptoms tend to recur because we cant splint a ribcage like our legs and arms. we need to breathe and that doesnt give enough rest to the inflammed part. i suggest u should get an xray of that part to find out the exact reason behind it. a rib belt, analgesics ,rest,hot fomentation should help. avoid sleeping on the inflammed side and avoid lifting heavy weight. I hope your question has been answered. If you have any follow-up queries,feel free to consult me anytime. Thanks,Take care,God bless.