Yes, there are test kits for ammonia (may be also known as NH3).

If you're using a water conditioner like Prime or Amquel, or want to in the future, then you'll need a salicylate-based tester, or you'll get false results. These are the two or three bottle reagent testers, or dipsticks (which are usually less accurate than the reagent ones). One bottle testers are nessler-based, which will work with other water conditioners. Note that this only applies to the measurement of ammonia.

I would definitely recommend getting one. NitrItes can also cause some of the behaviour you're describing, as they can bind to the gills and decrease the amount of dissolved oxygen the fish can get in.

Here's some more info on dealing with params in general, and ammonia.

~Ash