Recently came across a problem of turning on the shower, but no water is coming out. No problem with the sink or toilet, just the shower. The shower is against an exterior wall and it was pretty cold last night, so I'm wondering if the water in the pipe froze? I checked the basement and there is no burst pipe, so maybe there is lack of insulation around the pipe inside the wall that caused this?

Am I way off base and could it be something else? Any way to fix it without calling a plumber? Thanks for any advice.