Yes, sounds familiar. Definitely worth asking to see a rheumatologist.
I am assuming you are in the UK from your sign-in name. If so, check out the
www.nass.org.uk website (the UK national association), and in particular the "S-factor" campaign - this lists features of inflammatory back pain and says if you have them, then you could have inflammatory arthritis. If you print off the poster and take it to your GP, then you might find you get taken more seriously about it, as otherwise, at age 53 they will be likely to just immediately say its mechanical pain.
When you do see the GP first, I wouldn't bother mentioning the kleb (for most medics its still an insufficiently proven theory), but definitely mention: morning stiffness, and the fact that it relieves when you move; the family history; the fact that it started very young. HLA B27 status is something the rheumatologist may check out, but I'd avoid getting the GP to test for it initially, on the basis that if it is negative they could easily totally reject the possibility of AS (not realising that you can be negative and still have it), and because it isn't part of the diagnostic criteria anyway. If you want the GP to get started on testing, then ESR and CRP (inflammatory markers in the blood) can be useful if they are high (but again, not always high and not part of diagnostic criteria), and if you do have significant pain in your SI area, you could also ask the GP to order a plain film SI xray in advance of seeing the rheumatologist.
Sounds like you are one of the ones (like my Dad) who has managed to get by without too many problems, but its still worth getting diagnosed I think - that way even if it doesn't help you, it may help explain chronic back pain in other younger relatives and help them get a diagnosis earlier. Also, you don't know when things might flare up big time and you really do need some active treatment. Diet and exercise are great self help things though, and you sound like you have got that nailed.
