Tendinitis?

My left foot has been giving me a lot of grief lately.
It's still more of a curiosity issue than a pain one at this point of time.

I asked hubby what could be causing the discomfort and he suggested tendinitis. I looked up the info though and it doesn't quite fit.
If my feet are flat, I don't notice anything at all unless I put pressure on the area with my fingers. The spot is almost in a straight line from my second toe (next to the Big toe) and is about centered with my arch but at the TOP of my foot.

When I point my foot, that's when I notice the discomfort. My skin feels extra tight and it almost feels like I have a cut. Moving all my toes together when my foot is flat doesn't really make any difference. But if I bend my toes as if I'm going to pick something up, I notice a lot of discomfort at the joint of my middle toe.
In fact, now that I'm poking and prodding, I think that joint actually hurts more than the other spot :?

I did not injure my foot. I'm sitting down for probably 80% of my day. I don't exercise except to causally walk. My shoes are slip on Dr. Scholl's with additional arch support (which need replaced).

Any opinion as to what the problem is and how to fix it?
I rub the area a lot and take Ibuprofen as needed. This has been an issue for about a month. If I jiggle my toes a lot, the problem initially gets worse but other than that, there's been no change.

**EDIT**
Hubby misunderstood me and thought the discomfort came about when bending my foot (flat).
I've been paying more attention to it throughout the day and there is some discoloration- a faint red(almost like a sunburn) starting closest to my ankle then going in a \ toward my pinkie toe (but ending well before it). If it's warm to the touch, it's so slight it's barely noticeable.