Hi so I’m 13 years old about to be 14

Patient: Hi so I’m 13 years old about to be 14 soon and i use to do competitive cheer leading. I just quit cheer about 2,months ago and ever since then I haven’t been stretching like at all I have just been sitting on my couch watching Netflix eating. And I NEVER had back pain before and now I am. I’m really scared idk why . I NEVER had it before until AFTER I quit cheer. And I don’t have very good posture as my teachers say and I like to crack my back ALOT. It started hurting on my upper left side by my back bone then moved to the other side and as I’m stretching it starts to feel a little better .do you know what it could be?

Doctor: