HI Casper! No those aches are not in your head. It is a commonly reported symptom of UC, plus it also seems to be an occasional side effect of Asacol (probably other meds too). What helped me was exercise, which surprised me as it seems counter-intuitive to exercise when you are aching, but for me at least it helped. Pilates, especially.
ack, 42, Vancouver BC
DX: UC (Pancolitis) as of Jan2009. Symptoms first began June 2008.
Current Meds: Ferrous Sulfate, plus various supplements
Previous Meds: Jan-Mar 2009: Asacol 800 mg (1 pill x 4 daily), stopped Mar14/09.