I had the exact same problem at the beginning of February, lankeela, the pain was excrutiating and could only get comfortable by sitting in the same position as you described.
I eventually relented and went to the doctor service and I got:
Diclofenac painkillers
Tramacet painkillers
Diazepam (I didn't know the effects of this until my colleague woke my from my desk half an hour after taking it LMAO!)
Gradually over the course of around 1 week I started to get better, but I also made an appointment with a chiropractor for when I was not feeling any pain at all (no way was anyone touching me while I was in such pain LOL!) and she has helped loads too, I haven't had so much as a twinge since then.