Pressure and pain mid bump when moving around

[sophie22]

I literally was almost doubled over in the street, the sensation was taking my breath away! It was doing it every few minutes for maybe 15 seconds and got better when I rested when I got to my mums. When I started walking home again it started again, not as Intense but still bad enough that walking was very hard. What's going on?! Resting I'm ok just a bit sore but moving around is causing this insane sensation, my tummy feels hard when stood up. Dunno if that's normal. I'm at my consultant appointment in the morning anyway. When resting my lower back aches mildly but that's it