Being 5 years older than you and male, my opinion my not be worth much. However, I too have lingering issues but with my knees. For the first 2-3 miles they ache. Once I am past that point, I'm fine and have ridden as much as 60 miles in a stretch, but usually my weekend trips are 30-40 miles. That said, it wouldn't take much during those first few miles to say the heck with it. I agree with those who say you need to push yourself more each day. I try to ride 15-20 miles daily and one long trip on the weekends. I am no athlete, in fact I had become pretty sedentary in recent years until deciding it was time to ride again. It had been 22 years since I rode a bicycle on a regular basis. The first couple of weeks were difficult, but now the days that I cannot ride, whether it's because of weather or conflicts, I really miss it. Keep pushing yourself and I think you'll see steady improvement.