Two things to try, shine up the frizzen roller, that contacts the frizzen spring under the bridle. And shine up the part of the frizzen spring it contacts. Also, check to make sure the frizzen and pan are not pinched together at the bridal pin. Maybe separate then a minute amount for free movement.
When I take the spring off the frizzen moves freely so I know it's something with the spring not the frizzen, is it possible for the spring to be installed wrong or too tightly? I may have screwed something up while messing around with it. My frizzen was always tight but never this tight.
The frizzen spring should be screwed or pinned to the lock plate, directly unde the bridle. There is also a pin (part of back of spring) between the screw and end of the bottom of the "V" of the spring. The screw mounts the spring to the plate, and the little pin holds it stationary so it doesnt try to swivel when the frizzen bears down on it.