I live in a townhouse and one circuit is particular flips on a regular basis. Has on it:

-garage door opener
-2 separate single bulb fixtures in the garage on a switch
-1 outlet in the garage
-a 3-bulb fixture in the kitchen on a switch
-a 2-bulb fixture in the bathroom on a switch
-a bathroom ventilation fan

It seems to go at random, even when nothing is being plugged in or turned on. Sometimes you can just flip the breaker, sometimes it will flip right back unless you turn off a light first.

Thanks!

If that's the case there is no way to tell without putting an amp meter on it.
The lights and bath fan are not much and the opener is the only substantial draw.

Sounds like a weak breaker. After a breaker has been tripped multiple times, the spring in it will weaken.I don't know how long you have been at this location, but someone before you could have possibly been running something on the garage outlet, such as an electric heater, and overloaded it a few times. Personally, I would opt for changing out the breaker, but DO NOT UPSIZE the amperage. The wiring is only going to be rated for a 15 amp breaker. If this does not fix it, then further troubleshooting would have to be done. A breaker change-out would be the cheapest fix, if that is the problem.

Any chance this is an Arc Fault breaker? It would have a red test button on the front.