Extreme back/shoulder pain, please help I'm only 16

My back has been killing me for years. And I've never had money to have anything done but go to the clinic (and I never did that). I'm 16 and i can remember it going back to as far as when I was 12. Its always been a slight pain until recently. Now it's a sharp stabbing pain between my right shoulder blade and spine. Sometimes I cant even carry boxes at work, raise my arms above my head, or even look down. I'm going to the clinic soon enough but I'm hoping maybe I can get some idea of what it is from here sooner. I'm going in less then a week.

Does the pain affect your pulse or your breathing? Does it feel like it is a muscular type pain?

Give had the pain so long by now that I couldn’t tell u if my breathing is affected. But it does feel like a muscle type of pain.

Are you aware if you grind or clench your teeth? If you do it when you are asleep you may not realise you do. I got terrible shoulder pain and later on neck pain that I found out was because I was grinding my teeth and moving my jaw around a lot in my sleep. It became worse when I was on antidepressants because it is a side effect. Also ppi tablets for acid reflux can make you move your jaw around. If you experience sensitive teeth particularly in the morning or if you ever feel like your jaw clicks or pops, you could grind your teeth.
Otherwise, have you been in an accident or had an injury in the past?

I’ve never been in an accident and I’m not on any medication besides ibeuprophen occasionally for the back pain.