Pain??? :(

I find sometimes, in the middle of my picking arm when i am doin exercise
e.g, 1234 type exercises up and down the neck, etc, i get some pain, maybe a cramp in my right arm, does tis happen to anyone else??
This is around 145 bpm as well, if that helps any.

I get a pain sometimes in my "fretting" hand, but thats only when I do w hole hell of a lot of barre chords.

If your feeling pain in your arm it's probably because your tensing up when your playing. Try to keep both hands/arms as relaxed as possible.

do you pick from the wrist or from the elbow, or both? I play from the elbow, I used to pick from the wrist and sometimes this gave me wrist ache. I heard somewhere that using the elbow alleviated some discomfort because it's a bigger joint (not lots of fiddly little ones). Lots of players do use their wrists though and don't suffer discomfort, I agree with Chris, try and relax a bit!
In summary, what you need's a big joint.

if you use your wrist you can cause epicondylitis. AKA as tennis elbow or picthers elbow if on the other side. The idea is that the tendons on your forarm are beginning to inflam causing a soreness where they commonly insert on the elbow. Strum from the elbow to prevent that not from the wrist.

Be carefull dude! you dont want to get yourself a chronial tendonitis.

Though the pain is mostly located in your wrist/forearm/elbow the problem originates in most cases from your shoulders (even if the shoulders themselves do not hurt). The problam is that most guitarplayers - especially the self tought ones - tend to tense up everyo muscle in their body while playing and some even stop to breathe for a while when playing something difficult. Apart from the fact that this does not realy contribute to a fluent and good play, it is also VERY unhealthy. I know some dudes who had to stop playing guitar because of that - forever. and i also know alot of dudes who get terrible headaces after a while of playing because they tense up and get a stiff neck. So try to find a relaxed position, and no matter how difficult the thing is you are trying to play - break it down, play it slowly and RELAX!