If you notice foul smells coming from your shower drain, the problem may be easier and a lot less costly to solve then you think. If there is no problem with the drain being slow, the water is flowing freely and doesn't back up into the shower, the problem could simply be that the inside of the drain is dirty.
First remove the two screws holding the drain cover in place. With your screwdriver and a little bit of pressure, you will be able to pry up and remove the drain cover.
Soak the paint roller cover in the bucket of cleaning solution and then place it into the drain opening. You should be able to insert the roller cover deeper into the drain using a gentle, back and forth, screwing motion, scrubbing the inside of the drain all the way down to where it meets the trap. Remove the roller cover and repeat the process until you can see that everything is good and clean.
Replace the drain cover, re-insert and tighten the two fastening screws, and you should be good to go. If the odor persists or soon returns, give Dragon Restoration a call at (937) 428-2626.