I Am 52 Yr Old, Male, 221 Lbs, 6'4", And

I am 52 yr old, male, 221 lbs, 6'4", and moderately active. I have not been sick recently not had any cold or fever. But I have noticed a significant increase in muscle soreness and joint stiffness after exercising. I normally bike 16 - 20 miles, or jog for 2miles abound 3x/week. But I ran the other day and my quads hurt for two days. There are more experiences than the one I just gave, but it is a good example. The soreness is not limited to lower extremities. Not sure why the sudden increase in muscle pain??