I had one as well for 2 days post-op.
Some doctors use them, some don't. My understanding is that it depends on your surgeon's technique & preferrences. They're used to drain excess fluid (blood, fluid pumped in during surgery, etc) out of the abdominal cavity. Depending on how the wounds are cleaned & how much fluid is drained at the end of the procedure in the OR (and how much of a bleeder you might be), you may have a lot of drainage or no drainage at all.
I had little to no drainage, but my surgeon kept my drain in until the morning of my discharge. It didn't bother me. I sometimes felt twinging pain in my left shoulder, but this is normal. The drain kind of butts up against a nerve that runs up to the shoulder, and this can cause pain for some patients. It wasn't really all that uncomfortable, or painful. It was just sort of there. It honestly didn't bother me much. I was more concerned with trying to get fluids in amidst all the tummy gurgling, hiccuping and burping. Hiccups were more painful early out than any of my incision sites or the drain. Overall, I had minimal pain/discomfort from either the incisions or the drain, and as far as pain meds go, I was on IV tylenol the first day & night post-op, but didn't need to take anything after that.
Hope it helps,
Somayeh
Defining success by behaviors, feelings and NSVs!