Not a silly question and welcome aboard! What you are describing is not the expected response. What you might try next from either a shallow cruise climb or straight and level flight, is to simply engage the A/P on the 172 or G36, and see what happens next. The pitch angle should be maintained as well as the current heading. Anything else means something is wrong with either the sim or your controller(s) set-up. If the A/P response is as expected, try engaging HDG mode to see if a turn is commanded to the selected heading. The bank angle should not be extreme. Good luck and let us know how it goes.