Stress Fracture???

I am a distance runner that recently increased distance to be able to compete in January at the local marathon. I developed pain in my left shin area then is moved to my ankle area. increased with the increase in distance anything over four miles and I am literally in tears in pain. I went to the Doctor and X-rays revealed nothing, so he did an MRI. there lies the problem. the results are conflicting, see for yourself:

FINDINGS:there is mild edema along the anteromedial margin of the mid tibial shaft, possibly peristcal reaction related to low-grade medial tibial stress injury. There is no marrow edema or stress fracture. There is a small tibiotalar joint effusion. The fibula is intact.

Could someone please put this in layman's terms? do I or don't I have an injury here?

[sonu78]

Hi,
It is not possible to comment on the problem you do suffer from.
Would try to explain a bit about your MRI findings.
small tibiotalar joint effusion point towards some joint pathology. Being a small joint , could suspect some type of arthritis. Intact fibula and no fracture rule out stress fracture.
Marrow ( hollow cavity present within long bones) is free of any collection signifies no obvious infection of the bone.
Kindly consult an orthopedician