Hi diego, sorry to hear of your pain. Try this out, it is an exercise taken from "combat conditioning". You may not have heard of it, but it an exercise book thatcan be purchased online.
Ill try to explain it so you can start right away b4 ordering the book.
Stand against a wall, and take 3 steps heel to toe in front until you are about 3 feet from the wall!! Now have your feet shoulder width apart, and lean backwards, letting your head fall back and try to walk down the wall with your hands until you reach the floor. This may sound crazy to you. But stay with me.
This exerise is just one of many exercises taught in "combat conditioning" and also happens to be a graet healer of back pain. Please act on this post it will help you. Good luck with it!!!!!