How to Stop Pocket Doors from Scraping on the Jamb

Regarding your question on tools to remove the track, this article (Natural Handyman - How To Repair and Adjust Pocket Doors) says:

Many pocket doors can be adjusted with special tools from around the top of the pocket frame with the door in a partially closed position. These tools are often specially angled wrenches designed to fit into that little gap. These tools are part of the assembly kit supplied with the pocket door, but are rarely given to homeowners by the builders. Without these proprietary tools, you have to improvise with or modify standard tools.

If you can't get to the warped part of the track with any tool that you have (or can find), then you will need to cut a hole in the wall for access.

This article (Ask the Builder - Fixing a Pocket Door) has a great description of how to get access to the track. The article talks about replacing the track but it also gives a warning that if the new track is not the exact same dimensions then the little project will become much bigger. So you will have to make a decision to cut the wall to get access to the screws to replace the track or just to get to the warped section of the track.

A quote from the article:

Remove the door from the pocket and take it off the track. Use a flashlight and peer up into the pocket cavity. There is a good chance you will see the screws that fasten the track to the frame. It is now time to cut an access hole on one side of the pocket wall. This hole will allow you to get your hand or arm into the pocket so that you can loosen and remove the screws and subsequently the track.

I had the same problem, and was able to resolve the problem by counter-bending the door. You can try it in the frame, or you can remove the door and use some wood you might have laying around. If you do it in the frame, you won't be able to operate the door while you're working on it, and it will probably take a few days. But the idea is to stick some wood or something to make the door bow the other way. You'll need to be creative so you don't scrape-up the door. If you can figure a way to counter-bow the door by hand, then slip the scraps of wood in there, that would be good. Maybe put the top and bottom scraps in there, then get someone to heave on the middle section while you slipped another scrap of wood in there. Trying it in the jamb might take longer because you can't get that much of a counter bend in it, due to the frame only being so wide. Taking it out of the jamb might be faster, since you can get more of a counter bend, but obviously removing pocket doors can be tricky.