Forearm Muscle soreness from beginning lifts

[stktrader]

Male 66 yo. I still work in the hardwood floor business so i am in pretty good shape. I noticed that my arm strength is not what it should be so I joined a gym which is free to Medicare members. I started out on the treadmill, then stretching and finally doing various lifts with dumbbells progressively. 10, 12, 15 lb at 20 reps each. Then 20 lb at 10 reps and the 25 lb at 8 reps. That was Friday. Inner elbows were sore but not that bad. That went away by Monday but I now have a sore left upper forearm muscle. It gets sorest when I extend that arm. Do I have to wait until that soreness goes away before lifting again? I assume I should stop those last two 20/25 lb reps for a week or two until I acclimate to this routine. tia

[plugeye]

might be tendonitus. i'd cool it until all gone