The answer to 'why is my drain cleaning' is that a clogged or slow-draining drain is a common plumbing problem with several potential causes. The most common reasons include hair, soap scum, and other debris buildup, as well as tree roots or foreign objects obstructing the pipe. Symptoms may include water draining slowly, gurgling sounds, or foul odors coming from the drain.
For minor clogs, you may be able to clear the drain yourself using a plunger, drain snake, or chemical drain cleaner. However, for more stubborn or recurring clogs, or if the issue is deeper in the plumbing system, it's best to call a professional plumber. They have the specialized tools and expertise to properly diagnose and fix the problem.