I don't know for sure, because I've not worn a mask, as I've not yet been in a situation where it might be expected. But I'd expect it to become physically uncomfortable after a while. The other issue I have with masks is this:
As this supposed new research saying that masks are now a good thing hasn't been brought to my attention, I'm still unsure whether or not to abandon the earlier received wisdom, i.e. that at best masks provide only marginal protection and in many cases can do more harm than good. So if I were to have to wear one, I'd be mindful that I might be simply being forced to take risks myself just to make others feel safer from catching the virus from me. It seems rather odd that most of the current "information" that's coming out about masks says nothing about how to mitigate the risks associated with masks - almost as if it's a political thing that's going on where they don't want to mention the risks in case it puts people off wearing them. So, for me, the potential danger of masks is a bigger issue than a bit of of discomfort, and I'm just glad I haven't yet needed to come out of isolation.
If at some point I do have to compromise on proper precautions and wear a mask for a while, I'll research its safe use and handling carefully, which will probably involve the use of disposable gloves, dish soap, and sealable plastic bags.