I've had several female patients present with lumpy, painful forearms after significant hormonal changes (postpartum, perimenopause). The nodules feel very similar to those that formed on my thighs after I had suffered multiple fractures to my pelvis. They showed up months after the trauma, were massaged out over a period of six months, and recur on occasion. The difference seems to be that these women have pain with use of the arms; I had pain only with pressure on the nodules. Both feel like the beginnings of scar tissue if they don't get worked out. Fortunately, both tend to be responsive to friction.

It's not uncommon for women to have major, unexpected changes in their bodies after hormonal changes. Many women report that their health changed either for the better or for the worse after a pregnancy. Some women experience change in hair texture (straight to curly) or a change in how fast their hair or nails grow. But the lumpy, painful forearms is something I've not heard of before.

A Google search yielded no relevant results. If you have experience with this, please let me know.