The above poster is correct in suggesting asking for a Colonoscopy. So many IBDers seem to be labelled as IBS, and it's really IBD.
'Tailbone pain' is commonly reported in IBD posts here and in the Facebook IBD groups postings. IBD is known to cause arthritis-like conditions. One kind mentioned is pain in the 'tailbone'.
The medical term for it is "Enteropathic Arthritis" or "Enteropathic Arthropathies/Arthralgia".
Do a search for "tailbone" here on HealingWell.com -- and the pain conditions that come up in the search results are among *mostly* IBDers (Ulcerative Colitis and Crohns).
I have it too. Was initially told it was "IBS". Finally had a Colonoscopy and the biopsies showed "ulcerative colitis" cells.
Post Edited (emmaleechase) : 7/12/2014 9:34:10 PM (GMT-6)