We had a lady join our club who was a total beginner. I ran with her a few weeks, doing 1 min run 1 walk, then 2 run 1 walk, etc building up each week. Then all of a sudden she could not run at all without calf pain, she described it as having two bricks stuck to her calves.
She then went for sports massage - I warn you it is painfull, and the next day she was full of bruises, but it was worth it, after a few sessions she is now running pain free. (wrong shoes were also her problem)
The trouble is that if you don't get rid of the knots immediately, they just get worse each time you run until eventually you will do some damage just like Wee Piglet.