Hi...lower back pain is common with flares. Arthritis (there are different kinds)...some can be associated with UC/IBD, but not all. Osteoarthritis isn't...which most people have, but I would think that the pains and discomfort associated with it could be exacerbated by flares (or periods for females).
You should definitely get checked out anyway to make sure you don't have anything else going on. Blood tests can be done as well to see if there's any actual connections.
Your back ache could be an early sign of an impending flare, your period, ovulation, nerve impingement, strained muscles...etc.
I can relate big-time....
*Heather*Status:mini flare June 23* 6asacol daily+ Salofalk (tapered every 3rd night)
~diagnosed January 1989 UC (proctosigmoiditis)
~5ASA: Asacol + Salofalk enemas (increase for flares tapered to maintenance)
~Bentylol (dicyclomine) 20mg as needed
~Probiotic 2 (Natural Factors Protec) + 1 (Primadophilus Reuteri) at bedtime
~Natural Factors Multi Digestive Enzymes with supper
~Ranitidine,Pariet (reflux) Effexor XR 75mg; Pulmicort/Airomir (asthma)
~URSO for PSC (or PBC) 500mg X 2 daily (LFTs back to NORMAL!!)
My doc's logic.. "TREAT (FROM)BOTH ENDS" worth it !!!