The answer to 'my pipe smells bad' is that there are a few common causes for a smelly pipe, including a blocked drain, a dry p-trap, or bacterial growth. The symptoms may include a foul odor coming from the pipe, and the solutions can range from a simple DIY fix to calling in a professional plumber.
If the smell is coming from a sink or shower drain, it's likely due to a blocked drain or a dry p-trap. You can try using a plunger or a drain snake to clear the blockage, or pour some water down the drain to refill the p-trap. If the smell persists, it could be a sign of a more serious issue, like a clogged sewer line or a problem with the septic system, which would require a professional plumber to diagnose and fix.