Aching shoulder pain when doing dumbbell curls

[i3ighead]

I get a burning/aching sensation in my left shoulder whenever I do high volume bicep workouts. The pain is close to or between the shoulder blade/rear deltoid area. This is ONLY when I rep high with many sets. The discomfort is so great that I have to stop my set. My right shoulder is perfectly fine. I can keep repping it, but my left shoulder prevents me from curling any further. I get this pain when I perform the curls sitting or standing. Anyone know what is wrong? All comments appreciated.

Also. Why is it forcing me to do a poll. I have no idea how to take it out. I am a newb. Sorry. Just ignore the poll.

[mrExtreme]

It sounds to me like your form is faltering and you're pulling more with your back than your bicep on the left side.

[l0stsheep]

it makes sense to me that you only get the pain when you do high reps because you are doing more movements. Like Senor Extreme said, I think your form is off...A curl should not use the shoulder. If your elbows are coming away from your side when you curl, then you are using your shoudlers. Keep your elbows in place when you curl, this will prevent you from using shoulders and will give the biceps a better workout as well.