What model of boat?

In my experience, difficulty in raising a sail can have a variety of causes.

The easiest item to fix is batten tension. If the battens are really tight, the sail will be harder to raise.

Beyond that, the hardware issues are varied.

Start by looking at the sail feeder (if installed), be sure it isn't binding the luff.

Next, look up the length of the mast track to be sure there aren't any parts that are pinched (restricting the luff from passing through).

Take a look at the entry of the mast track to make sure it doesn't have rough edges left behind from the manufacturing process (this is more common than you would believe, and will cut your sail very quickly). Use a file, followed by emory cloth to remove any burrs or other imperfections.

If you have a comptip, check to be sure that its track isn't pinched, and that it is correctly aligned with the mast track.

Also, check the halyard blocks to be sure they aren't binding.

As for the sail, you can look at the luff to make sure there aren't any issues with manufacturing, such as material doubled up on the luff that would make it larger than intended.

Hope this helps!

Mike