First, release the Caps Lock on your keyboard. USING CAPITALS IS LIKE SHOUTING!

OK, now. You may be trying to run before you learn to walk. The techniques you developed in learning to play classical guitar will be useful, but there are some new things you must absorb.

Holding the pick. If you try to pinch the pick between the tip of your thumb and the tip of your index finger, you will set up all kinds of problems for yourself. Make a fist with your pick hand. Put your thumb up on top of your fist. Now slowly uncurl your fingers until just the part of your index finger from the tip to the first knuckle is still under your thumb. The pick goes in between your thumb and the side of the finger. This allows you to stroke the strings, by rotating your forearm. Your forearm should be parallel with the strings.

Now then, about this solo. Put it aside for a while. Play some scales, slowly, alternating downstrokes and upstrokes by rotating your forearm. The edge of the pick should 'shave' across each string. Don't hurry. Use the metronome to keep your pace steady. Very gradually increase your speed, a little bit each session, only if you have mastered the technique at your slow speed.

After 7 years of classical music you should be familiar with the benefits of practicing technique. Proper pick action should soon feel natural, without causing soreness in any joints or muscles.