second, you obviously seem to believe that the problem lies in your picking hand (i'm assuming you're right handed) as you've mentioned it several times. so you have half the battle won, inasmuch as you know the problem. now its very difficult to propose specific solutions without being able to see you play, but i can suggest a general solution that works almost 100% of the time....
Slow down.
play through your scales, sweeps, exercises etc, but take the tempo waaay back, and just watch your picking hand. observe how you hold the pick. watch where your palm is sitting. do you tend to rest your pinky on the body? (i always recomend not doing this, i think it restricts movement, but some players find otherwise... its a bit style dependent). are you picking at exactly the same time as your fretting hand is hitting the note?
if you've been playing for 7 years, you should be able to be your own worst critic, but you need to play slowly and observe what you are doing in order to be able to make changes to your technique...
hope that helps
