I'm A 16 Year Old Girl And I've Been Having

I'm a 16 year old girl and I've been having pains on my lower back / coccyx! It's been on going for almost a year I believe! I already had lower back pains but it got worse when I started training at the gym! I can't arch my back and when I bend down to pick up something it feels odd! I don't train anymore but everytime I start working out (I don't do intense work outs just basic stuff) the intense pain comes back my lower back even gets swollen at times and I feel a bone sticking out when I touch around my coccyx area! My trainer even asked me if I had scoliosis once. I also cannot lay on my back because it feels weird and it slightly hurts.. I really wanna know if I should get it checked out and what it might be? I've been avoiding the doctors!