hip pain

i have a 14 yr old daughter who has been suffering for several months with joint pain in her finger, knees, elbows and mainly hips, with most of her joints cracking on movement. my main concern is her hips as her right hip regularly ‘locks’,she is unable to move it(sometimes for upto two hours)and it is extreamly painful. she has a very limited range in both her hips and knees.Her consultant has said it is due to her bones growing to fast. she is now having hydrotherapy once a week with excercises as well. however she has been going to hydrotherapy for six weeks now and if anything she is getting worse she is now having to use a crutch to support herself as not only does her hip lock her legs sometimes give way. she is also on diclofenac and paracetamol three times a day.