What To Do For The Pain And Discomfort In The Shoulders?

Im 15 and i was on holiday last week with my school. We were playing a game in the sea to see how many people we could have on our shoulders. When I went to lift 4 people onto my shoulders, as i was leaning up out of the water with them on my shoulders i think i heard something click in my right side lower/mid back and it started hurting. My back didn't hurt whilst i walked but it hurt when I leaned back. A week later (today) I still feel a slight pain in my lower/mid right side of my back. Could this be serious and is there a chance that it could stunt growth?