Sharp pain under left breast

I have scheduled an appointment with my doctor but it isn’t until Thursday so in the mean time I’m scaring myself but I was wondering if anyone has had the same thing happen, under my left breast I feel a sharp stabbing pain when I breathe or just in general and recently it’s gone all the way towards my back so if I move to bend over or breathe it hurts. Could anyone know why? There’s no rashes or anything on me