I have multiple nodes underneath the skin both of my inner forearms. (size <5mm, non tender, symmetric). no others found on body. are they lymph/cyst?

Those really need: to be examined by a physician to determine exactly what the origin may be. It is impossible to tell by your description and assumption that they are lymph nodes. My guess is not but needs to be confirmed by exam

Fatty growth: These may be multiple benign fatty tumors called lipomata,but without seeing and examining them,one can't make a definite diagnosis. Your physician can evaluate them.