I moved a fridge into my garage. After about 2 mos, it started popping the breaker. I tried the other outlet in the garage, same thing. I ran a heavy-duty extension cord to a storage room off the garage and it is working fine. Just as an FYI, the home was built in 1986 and the fridge is a side-by-side about 10-yr-old. There were no problems with the breaker when the fridge was in the kitchen. Also, I can run my electric weed eater and leaf blower off the outlets in the garage with no problem.
If it's a GFCI breaker, then it's common for fridges and GFCIs to not get along so well.
If it's not a GFCI receptacle, you'll want to make sure the fridge is not overloading the circuit. If you've added anything new to the circuit, then that may be the case.
If neither of these are true, then it could be as simple as the breaker going bad. They are a mechanical device, and can go bad.