Let me preface this post by saying I haven't been officially diagnosed by a "medical professional" but there is a family history of tendonitis, especially in the afflicted area: forearms. I use my forearms a lot when I train, and lately, especially the day after training I'm sore/tender beyond what I would believe would result from my workout. Even more concerning is that I'm experiencing some weakness too. The targets of my workout get sore and heal and I feel stronger, but the pain persists in my forearms…
Any suggestions on how to combat this affliction whether it is tendonitis or not?
Rest. I've gotten tendonitis in my forearms before when I was rock climbing regularly, and the best solution is just to take a break from whatever you are doing that aggravates it until it heals. I pushed it for a while, and now I believe that I have noticeably less grip strength in the affected arm. It might also be a muscular imbalance, and not an aggravation of the tendon- in which case in addition to resting your forearms, you might also try to do some strengthening/mobility exercises... i.e. if it is a problem with your flexors, try strengthening your extensors, and vice versa.