I went on a ride at a fair kind of thing on the 30th of may, it was called a twizzler or something, anyway it was two seater and required that the largest person sit on the outside, so being a gentlewoman I volunteered to take that seat and my friend, who is the same build and weight as me, sat next to me. When the ride started it was fine but then my friend started sliding away from me when we went around one half of the ride and slammed into me for the other over and over, I was in absolute agony, I almost cried when I got off the ride and tried to sit down on the waltzers. (another spinny ride but less body smashing) I was in pain the entire night and it hurt to laugh, the top of my arm swelled and has developed bruises but its my chest that is worse.
The next day it was awful and it hurt to take deep breaths (normal ones were fine but when I sighed it hurt) if I moved a certain way it would push me to near tears; I was packing to go home from university so I hurt all day.
Today it is worse still, moving my torso at all hurts, twisting, bending, using my arm, pressing on my chest; all make me grit my teeth, gasp or cry out. But when I try to explain to people how much pain I'm in they think I'm exaggerating and don't help at all.
Its only on my upper left side because that's where I was being slammed into the side of the seat at, its mostly under my breast but its gone around by back as well and if I push between my breasts the pain goes straight through between my shoulder blades. Doctors are shut all weekend because of the Jubilee (I live in England) do I need to go to A and E? I don't think I've fractured or broken anything, I'm in pain but I'd know if something that serious had happened. What can I do to make it stop hurting other than pumping ibuprofen into my system all day?

Sounds like just a bruise, most likely can wait till your doctor is open