Is this a compound bow? I am guessing that it is.
A quick check is to examine the ends of the limbs where the bolts are. If one is wound in more than the other, the under
side of the limb, at the end, will be higher compared to the other; you will see a bigger gap between the lower edge and the end of the riser that it moves towards when tightening the bolts.
Sometimes limbs stick when the limb is wound fully down and the gap I mentioned is closed. The bolt will only turn one way and that is outwards. Sometimes when bolts stick, it's because the limb bolt has been wound out too far and the bolt is forced against one side of the threaded portion of the riser. so winding that one in is the best way to go on that bolt.
Some limb bolts are locked down with a separate lock screw. Those screws will be going in from one side of the riser, so they can pin the limb bolts in place. If your bow has those, unscrew the lock screw a little. If the other limb bolt is loose, its lock screw may have come slack.
If you use a bow press, the press needs to allow you to remove the string and then to allow you to unwind the press to a point well beyond the starting point, so the limbs are only lightly under pressure. Be careful not to unwind too far or the bow can fall apart and getting the cables back can be tricky unless you know exactly where they go. Some presses allow you to press the limbs just enough to remove the string, put another back on , and then unpress. That is no good for this job as the press remains on the bow (under pressure) so the bolts remain as tight as before.