Stretching muscles on freedives ?

I'm still very green in freediving, so i want to ask a piece of advice here.

This week i took my first dives into 6 meters deep, pretty much just going down there, taking a look at mother natures best views and then quickly up. Suddenly on one trip down i felt a non-sharp pain just above my left eyebrow. I thought maybe the mask had somehow slipped or smth alike, so i went to shore, adjusted the mask. Tried again. On the next dives i got that uncomfortable feeling again at already a few meters. So i called it the day, not a good idea to climb around in water if something is distracting you.

Is it possible that the pressure difference cause the mask to stretch my face muscles a bit and that is the reason for the weird pain ? It isn't "sharp pain" nor is it strong, but i'm slightly worried about this. I went down and came up with some pretty good tempo but i thought this should be an issue for freedivers, especially at such shallow waters.

PS. It has pulled back a bit over the few days.

Anyone ever had an incident like this ?
(didn't post it to accident/incident forum cause that seems to be mostly about scubas and their things, this place seemed more appropriate)

Mask squeeze? Press your mask firmly to your face and see if you get the same effect. If so exhale into your mask thorough your nose as you feel it compressing. Remember to equalize your ears as well. It may have been something happening in you sinuses as well.

Pete