i had a sudden onset of lower back pain around the tail bone starting about 5 days ago, i would have said it was mild to moderate and i'd be uncomfortable in a few positions. But today, It has suddenly become excruciating and have very few comfortable positions. Going from seated to standing has me cursing. I cant remember lifting anything remotely heavy or getting myself into an awkward position. I have however gained a lot of wait in the past year(10kg on top of 10kg from the previous year) and my diet has not changed much at all, so it's pretty uncontrollable. I had been going through a pretty bad fatigue phase so I had not done much walking in the past weeks-months. But in the week leading up to this pain I probably walked a total of 2.5 hours in the space of a few days. I dont know if it has anything to do with it, i didnt feel any kind of pain when i was doing those long walks.