Pain in forearm

[eXistenT]

I started training at my local gym with my girlfriend 4 months ago, going 4 days a week splitting bodyparts in all those days.

After a while I started getting this bad sensation in my forearm when doing basic bicep curl with dumbells in my brachioradialis, or it feels like the pain comes from there. But when i do a hammercurrl the pain is not there and I can even do heavier dumbells. I even feel the pain to a certain extent when using the EZ curl.
I feel like this is preventing me from getting further, the pain makes me totally lose all the energy in the beginning of the motion, I can bearly do 12Kg's. But doing hammer curl i can do 18 - 20 KG's without pain. This is so weird, becaause hammer curls hit the forarms more than biceps curls, but why is it that I feel no pain at all doing hammer curls?

I really want to add more weight too my bicep curl to get that peak, and if there is anything that I can fix it I would be very happy to get help!

[SubWooferCooker]

If its causing pain use the lighter weight and more reps, You don't need to add more weight to "Get that bicep peak" Just progressively overload, increasing reps is equally as effective as increasing weight, you will most likely find in time once you have increased the reps and got stronger you will then be able to increase the weight without pain, listen to your body.

[eXistenT]

If its causing pain use the lighter weight and more reps, You don't need to add more weight to "Get that bicep peak" Just progressively overload, increasing reps is equally as effective as increasing weight, you will most likely find in time once you have increased the reps and got stronger you will then be able to increase the weight without pain, listen to your body.

Hey, the thing is that I have been working out before. Progressive overload, adding weight and reps as my arms build their strength up. First time I literally had to start with 8 Kgs only doing 6-8 reps for 3 sets. Built my way up to 16Kg's doing 8 reps, 4 sets. But as I got the pain, I had to switch down to about 9 - 10 Kg's dumbells. It's a like rapid 6-7 Kg loss in weights being used. MY question is if this is an injury or not? And why does it not affect me doling hammer curls?