I used to get this a lot......it was similar to having shin splints,only on the forearms.
I was going way too heavy.
I`d rest up until it was gone,then go lighter with the focus on slow reps feeling the biceps do the brunt of the work,and squeezing at the top, followed by a slow negative.
I experienced this same thing when I first started training with weights. It was always after doing a set of straight bar curls, and it occurred after releasing my grip on the bar. Thankfully, I did not have it consistently for more than a few months, and it was never harsh.
However, I distinctly remember that slowly
releasing the tension in my grip when setting down the bar greatly reduced - in many cases, totally alleviated -
the splinting sensation.