When the running bug gets a hold of you, it doesn't grip light.
(It gets you in a cop-like arm lock, only this time it's pleasurable)
You live running, you think running. You literally breathe running.
Got toothache pain in your lower leg? Like when the anesthetic wears off in the dentist?
(Or a gummy rat gnawing on your shin bone like a corn cob)
It's shin splints, aka medial tibial stress syndrome. The scourge of new runners.