What Causes Sharp Pain In The Rectum?

For over a month, an area that seems like my rectum has, more often than not, had sharp, stabbing pains. Neither cold nor hot packs bring any relief. All times of day and night. Have been taking 2 tramadol to relieve pain so I can sleep at night. No tingling down legs. I have IBD, Parkinson s, Fibromyalgia, degenerative arthritis (including 4 bone spurs between L5 and S1), and just recently urinary incontinence. My internist can t see me before the first of Jan. I m not sure whether to try to see my gastroentologist or pain specialist, both of which I can probably see within a week usually.