Brief Answer:
Can be due to muscle cramps.

Detailed Answer:

Hello,

Pain on the side of the calf can be due to muscle spasm or cramp in the hamstring muscles. It is common in people who don't warm up and stretch properly before moving their muscles.
Doing too much,too soon and too fast creates problem
Repeated injuries cause formation of scar tissue and subsequently complete healing doesn't take place .
Other factors are
Poor fitness levels and lack of regular exercises
Poor nutrition and obesity
Some times referred pain from bulging discs is the reason.

Treatment is done by
Rest
Icing of hamstrings
If pain,take anti inflammatory drugs and local gel
Stretching of hamstrings by pulling both legs towards chest with hands below knees
Full recovery takes 3 to 6 weeks.

Prevention
Take enough calcium, vitamin D3 and B complex vitamins
Do stretching for 15 minutes before you run.
Use proper shoes
Strengthening your hamstrings.

I hope this answers your query.
In case you have additional questions or doubts, you can forward them to me, and I shall be glad to help you.
Wishing you good health.
Regards,
Dr. Praveen Tayal

---

Brief Answer:
Details below.

Detailed Answer:

Hello,

1) You need to do more stretching and warm up before running.
2) You can have Corcium C and Tab. Neurokind Forte for relief.
3) You can use an analgesic gel like Relaxyl gel after icing.
4) You can have ibuprofen for relief. In case the pain is persistent then do consult an orthopedician for an examination and a few blood tests.

Hope my answer is helpful.
Do accept my answer in case there are no further queries.
Regards.

---