A clogged shower drain usually goes hand in hand with a bad smell. Drains have traps which keep the sewer gases from entering the living space, but that isn’t what normally causes the smell. People with long hair are plumber’s favorite people. The hair gets caught going down the drain and it combines with other hair, soap, and shampoo for a rat’s nest of foulness. Your job, should you choose to accept it, is to pull the rat’s nest out of the drain.
This isn’t as hard as it sounds. Commonly you will find the clump of hair in the trap so you only need to get a foot or so past the drain cover.
Remove the drain cover and use rubber gloves (the drain has plenty of germs down there). You can use a snake if you choose, but before you go through the hassle, try using some simple tools first. I like a product called a “Zip-it”. It is a cheap strip of plastic about 18” long that has small barbs on it. The idea is to push the strip into the ball of hair and the barbs will catch the clump and allow you to pull it out. It works very well when the clump is at the trap. You can also finagle a coat hanger with a small hook on the end of it, but this only works well if the clog is between the trap and the floor. In other words, the plastic goes around corners much better that a metal coat hanger. As a last resort you can always go rent or buy a snake, but these quick and cheap fixes just might save the day.