Hi, my name is Mike and I have been in the home improvement and repair field for 20 years. I will be glad to help you today.
It does suggest that there is an obstruction. If you have a toilet plunger that would be the easiest first attempt to clear it. If that does not work then remove the shower drain grate and see if you can remove the blockage and if you do not see the blockage then you will need to snake out the drain with a drain snake.