Preventing Injury

[Minute Waltz]

I have recently come across some disturbing pain in my left arm when I practice, particularly scales, etc. It began as a mild throbbing when I loosen my hands to relieve tension during my rather grueling practice sessions. ( I shake and massage my hands periodically) For those of you who have read my other topic, allow to allay any suspicion: No, it is not because of the exercise I rather hastily posted in the aforementioned topic, seeing as I have yet to even begin the exercise, and I rather doubt I will. Now the pain occurs somewhat regularly when I practice. I play scales at the beginning of each practice (two to three times a day), three octaves, hands together (obviously) moving chromatically (C, to C#, etc.). I find this somewhat painful now.
If you've read my other topic, you'll know that I am nearly ambidextrous, and I also have exercises for left-hand writing, strength, etc. I do use a hand strengthener and I believe it is the source of the pain. I have stopped this exercise, naturally.
Getting to my question, finally: What can I do to heal this pain? It is on the thumb-side of my wrist/forearm. It is not a severe pain, but I believe it has the potential to be. What can I do? I have stopped practicing, but what can I do to get back into good health? Any suggestions would be greatly appreciated.

[jazzyprof]

Let me say first that you are doing the right thing, to stop playing for a while.  Give your body time, a few weeks to heal.  During this time you can do mental practice away from the piano.  Read closely the scores of the pieces you want to learn.  Analyse passages, work out fingerings, memorize.  This work will pay off handsomely when you finally get back to the piano.

Next, if you can, see a doctor.  It would be good if this doctor knew something about sports medicine.

Finally, it seems to me, from reading this and your other post, that you have been focusing perhaps a bit too much on pure finger exertion and the notion of "finger strength".  You said two things that alarm me.  (1) Your practice sessions are "rather grueling".  There is no reason why practice sessions should be grueling.  Now, if you were training for a marathon, a boxing match, or the Tour de France, I would understand the need for gruelling practice sessions.  Piano practice is ultimately about making music.  It should be pleasureable, not gruelling.  Technique should not be pursued for its own sake, separate from musical expression.  Perhaps when you finally get back to the piano you should limit your sessions to no more than 20 minutes at a stretch.  Then take a break.  You said that you practice scales as much as three times a day, moving chromatically through all the keys.  Do you mean you play through all the scales each time you sit down to practice, three times a day?  I believe that is way too much time spent on scales.  You said that you find playing scales painful now.  You should spend more time on repertoire, where you get a variety of motions, where you get to rest your hands, where you avoid repetitive stress from doing the same motions over and over.  By playing scales hands together, over and over and over, you are unduly stressing your left arm, which for most people tends to lag little behind the right, and is now having to work extra hard to keep up with the right.
(2)  You use a hand strenghtener.  That is also a rather alarming notion.  Playing the piano does not require that much strength.  It does not require much effort to depress the keys.  They aren't that heavy.  What one needs to play the piano well is coordination rather than strength.  If you keep that in mind you will stay away from potentially injurious exercises and devices. 
 

[Minute Waltz]

Thank you for the suggestions, but let me clear a few things up:
A. The hand strengthener is not for the piano, put for hand strength in general, to make my left hand stronger for the purposes of writing, etc.
B. My piano practice sessions are very pleasurable, and by grueling, I meant long and on a strict regimen. I begin with scales, move to my pieces, then to some technic, then to sight reading, etc.

Thanks again

[jazzyprof]

Another suggestion:  See if you can find a teacher in your area who is schooled in the Taubman method.  He/she can take a look at your technique and help figure out ways you can avoid injury.