Back sore could be from the saddle or other from compensating for some other pain source, such as sore hocks, SI joint, etc. You need to determine what is causing the pain, then figure out if a saddle pad is the correct answer.
My horses seem to like the sheepskin pads the best. Fleeceworks or Mattes. Both are expensive, but I like the way my horse feels/rides when using one. Thinline pads are also very nice. I try to use the Thinline pad when my horse is dirty, with a baby pad underneath, and the sheepskin pad when he's clean. Many people put a regular saddle pad underneath the sheepskin pad, but in my opinion doing so negates the benefit of the pad. But, as the posters above mentioned, a properly fitting saddle is very important.
ThinLine! Mare was starting to act sore (no underlying conditions, saddle fit issues, etc.) last year. Tried a ThinLine and it improved instantly. Now, DD and I use them each and every ride. That is a requirement for my horse now.
You need to figure out WHY the horse's back is sore and elimate the problem, not pad over it.
I would make an appointment with BOTH a vet AND a saddle fitter.
The vet (who should come out first) can assess whether there is a physical issue, either in the back itself or in another part of the horse's body that manifests as 'back soreness.'
The saddle fitter (who should come out when the horse is cleared by the vet) can make sure that the saddle isn't the problem. In the case of horses whose owners haven't read any books on saddle fit cover to cover and also learned some tips from regularly involving a pro-saddle fitter in their horse care routine, which most owners have not done, USUALLY the saddle is a problem. Maybe not the problem, but definitely a problem.
I say have BOTH the vet AND the saddle fitter out because vets quite often make poor saddle fitters. (Trainers also, btw, tend to make very poor saddle fitters. And anyone who says their saddle fits everything in the barn is definitely a poor saddle fitter.)
I have to third finding our why a sore back, Nothing you can add can FIX it. It may make him feel better for a while but the problem will only get worse if you cover it up. BUT if you want to add something that might make him feel better try and Back on Track mesh sheet....
HAve the vet out. My horses back was so sore from Lyme and it caused him to fall and he hurt his hip so I had to do shockwave and robaxin to fix it!
Mai Tai aka Tyler RIP March 1994-December 2011
Grief is the price we pay for love- Gretchen Jackson
"And here she comes. Is it a bird? Is it a plane? No, it's ZENYATTA!"
Thinline pads are good at reducing concussion without adding bulk. If your saddle does fit, then many of the therapeutic pads out there will make it not fit.
Saddleright pads are also very good and don't add a lot of bulk (although more than thin line pads).
I like sheepskin pads but they can add a lot of bulk.
Interestingly, a friend of mine had a mare who shows back pain periodically. She had the vet look at her and he said her sensitivity was "within the range of normal" . He suggested robaxin. When the saddle fitter came he confirmed that the saddle fit fine but found her to be very sore in her hamstrings . . . which was impinging on her hip. Some massage work fixed the problem and gave her owner a technique for dealing with it in the future.
Thanks for all the good advice! just a note my horses back is sore because shes sensitive not because of underlying issues so all I'm looking for is a pad to help.
ProLite pads are superb for shock absorption but if your saddle fits fine the way it is, it probably wouldn't work as they are a little bit too thick to go under a well fitting saddle because they will effectively take the saddle down a half or a whole tree size.
If your saddle fits well but you need a pad to keep her comfortable you either need to reflock the panels (maybe they have gotten hard) or buy a larger tree size to accommodate a pad.
You don't want to just shove a pad there and then have the tree be too narrow; you will swap out one problem for another.