I have noticed my oil temperature fluctuating lately, seemingly ever since I got my oil changed, but I can't say for sure.

Normally, it would just sit on the notch one to the left from the middle setting on the oil temp dial.

Now it it frequently will hit the middle notch, and venture just a bit past it.

When I got the oil changed, there was a leak, and a seal in the oil cooler broke "according to the mechanic".

I live in the bay area, so temperatures here are pretty mild, although it can be hilly when driving around.

What do you guys think?

Stop paying attention to that gauge. It will fluctuate with hills, stop and go......

If it starts getting really hot then worry. But what you described is normal...to me at least.