Hi, Ive been having lower back problems for quite some time at least for 6 mths now. The odd thing is that it happened when I decided to try the cabbage soup diet I was on it for one day with alot of bowel movements, I remember the pain that followed the next few days almost for 2 weeks, I coud barely walk, sit my kids had to tie my shoes, and it has never been the same since.
If you had a lot of bowel movements, with the cabbage soup diet, then there is a distinct possibility that you developed bowel problems, such as hemorrhoids from the straining. It is less likely to be mechanical/musculoskeletal back pain simply from a course of cabbage soup. I would see your doctor and have the gastrointestinal system checked. Another possibility is the Colonial Cyst, which is an infection of the hair follicles around the anus. This can swell up and become exquisitely tender, and would have to be Chat Doctor.  So, again, go see your doctor.