What is causing my joint pain?

I'm 16, and I have chronic pain in my back, knees, hips, ankles, and it's now starting in my elbows. I have stiffness in my shoulders too.

The back pain started when i was around 10, a little earlier than that, but not too bad. The knee pain started when I was 14, and the hip pain and shoulder stiffness when i was 15. Now I can feel my elbows and ankles starting to feel uncomfortable.

All my joints, and my back, are CONSTANTLY cracking and popping, especially my knees and ankles.

The back pain is usually mild to moderate, but it gets pretty extreme sometimes. Same with the knee and hip pain, only that's more on and off, but they almost always feel uncomfortable. I've noticed that within the last six months, whenever I put too much weight too quickly on one of my ankles, it jams it and it hurts a lot. My shoulder stiffness is constant, and I constantly have to lift my arms above my head and stretch them backward.

The only sport I do is cheerleading. I don't really know what causes it, obviously cheerleading makes it worse sometimes, but there has to be a route to the problem.