The most common side effects with CIALIS are: headache, indigestion, back pain, muscle aches, flushing, and stuffy or runny nose. These side effects usually go away after a few hours. Men who get back pain and muscle aches usually get it 12 to 24 hours after taking CIALIS. Back pain and muscle aches usually go away within 2 days. Call your healthcare provider if you get any side effect that bothers you or one that does not go away.
These are not all the possible side effects of CIALIS. For more information, ask your healthcare provider or pharmacist.
Maybe you have a stomach virus? Did you do any heavy lifting or anything else you can think of to flare up the h-roids?
Then again, cialis help blood flow to the "nether regions."