I started riding a bike for the first time in 20 years in September. I worked my way up from 3.5 miles to 20-ish miles by riding 3X per week (sometimes 4) the last 3 1/2 months. About a month ago I noticed a tight feeling in both hamstrings and it affected my power. I didn't ride for 3 days and they both got better, but then the pulling and tight feeling came back in only my left leg. Today I noticed it for the first time when I wasn't on the bike--I was just standing in the kitchen. On the scale of 1 to 10 the pain is only a 1. I have iced it after riding, but it's not improving. I have to be careful to pedal in easier gears, but obviously not using the legs for cycling in 20 years probably means weak muscles and lack of flexibility. I have been foam rolling it every day for a month. What else should I be doing? I don't want this to become a long-term problem.