What Causes Swelling And Pain On The Coccyx After A Fall?

I'm 18 years old and I fell on my coccyx 4 days ago. I slipped backwards and straight after it didn't hurt much, but the next morning it hurt to sit upright, lean on my tailbone, bend in most directions and the muscles also hurt when I stand up from sitting or crouching, or spin round in bed. It's stayed like that for the 4 days and seems a bit swollen. I've been taking painkillers, but to I need to consult a doctor or go for an xray?