i have been running since January and managed to get up to 6 miles . But now i am unable to run a mile without my right lower calf feeling very tight an heavy . I am trying ti train to do a half marathon in June . I also swim twice a week and have joined a milatry fitness group twice a week too . But my right leg is oreventing me from getting any further with my running . i have no idea why it has suddenly started doing this .
Hi welcome to Chat Doctor.  Thanks for your query. After going through your history I am in opinion that you have stress fracture of leg bone. To confirm please visit orthopaedician and have an X-ray of leg get done. Now you should avoid running, take rest, analgesics. If fracture confirmed on X-ray than continue rest plaster or crêpe as per requirement (as advised by orthopaedician). I hope your query get solved. Thanks.