Hey, I have been guitaring for 4 years..obviously not extremely regular but good enough. I have been observing that each time i try playing slightly fast leads or say playing palm muted riffs like of the song Laid to rest by lamb of god, I am able to play the stuff but my index finger of the plectrum hand becomes red and pains moderately. I thought the issue is that i put a lot of pressure on the plectrum when trying to play fast so i played slowly and checked. Yes i had no pain but the problem is that how long do i keep playing slow......my finger automatically gets tempted to play at that fast speed and voila the pain begins lol. Also while playing barre chords, I am 100% sure that my technique is right and all the notes ring evenly when i barre but say after 2-3 minutes of strumming barre chords my thumb pains Excruciating. I literally feel like cutting off my thumb in dismay. Can anyone please guide me as to what are my problem areas with the index finger and thumb.