Can't imagine your frustration to have the shutters, and one is being a brat.
My garage door spring broke one time with hurricane looming. Door was jammed halfway open. Garage door guy came right out before the serious winds arrived.
PB Blaster is far superior. Kroil may be even better yet but it's harder to find. Use the straw if there is one. Heat can help. Get a little wiggle in either direction, add a little more oil (and heat, if using that).
If the shutters have hinges, and you can get some taps on the ENDS of the hinges (where the frick'n pin is -- that every_thing turns on) that could be all the difference.
Without damaging the hinge, hammer blows can help loosen things. Provided the hinges are heavily enough made, if you can get to the hinges, oil them with whatever you have, then to spread the impact out perhaps use a wide (and hopefully -blunt-) chisel set with widest width along one side of a hinge. Give it some 'love taps'. Hit it from the other side too, if you can get to it. Go back to the head of the pin and tap-tap-tap that some more -- without hitting the shutters (with a wild hammer blow) or ripping out the hinges, or bending the hinges, etc.
Using short (forearm and wrist) strokes, deliver sharp blows ---but not enough to distort metal, or else rip the hinges out. You'll have to use your own judgment. Are the hinges thin? Or are they comparable to what's on a regular household door -- and in good shape? Look at the head of any screws. Are they small, and rusted? If so, then the blows may need be lighter. If big screws, well sunk into the material of the shutters -- and the material of the shutters is strong, then a bit more force -- a more solid, and sharper blow could be delivered.
Without panicking -- if you had the tools, a hammer, a selection of chisels, and maybe a 'punch' (to focus the blow on the head of the pin -- or even the opposite end of the pin as long as you do NOT round off the pin, or else the shutters could be all that more difficult to remove at some later date) and have enough experience with those type of things to be able to well enough guess how much force you can use without harming anything --- it could be all the difference. A hammer alone -- if used judiciously -- could make all the difference, provided you could get a clear, short but solid "tap" on the hinge's pin. Even a nearby blow on the flat parts of the hinges might help, although more directly concentrated on pin and coupling area is better. The shock of the impact(s) can serve to break things (like rust?) loose, perhaps enough to get things to move a little -- in which case using more oil and rocking things back and forth (increasing the range of swing a little at a time) can free up stuck parts with minimal to no damages.