You would be surprised at
You would be surprised at what constitutes a vitamin deficiency. The US FDA would have us believe that the only 400 IU of vitamin D3 is all that is needed when in fact, the amount is much, much higher.
A low level/Vitamin D deficiency can cause extreme muscle weakness and tightness that will not resolve on its own. Be sure they ask for a blood test to check your Vit D level, specifically 25(OH)D.
For everyone to consider when dealing with issues of tight calf muscles:
This advice is not such a long-shot...read on...
I had also experienced extreme muscle fatigue and tightening in my calves while running. My neurologist (treating for Morton's Neuroma) ran some blood work and found that I also had a Vitamin D deficiency. It was strange since I had been taking 1,000 IU of Vit D per night for the past half year. I did a lot of research to find out what to do about my problem. Apparently, they're finding out that the 400 IU per day the government feels is adequate isn't so, according to one article I read. The article stated that 93% of people who go to the emergency room (for whatever reason) are Vit D deficient. There may just be a hidden epidemic here. I found that doctors prescribe 50,000 IU once per week for those with Vit D deficiency. (I read on some of the Vit D discussion forums that some people experienced head aches, tremors, etc., when taking high doses of Vit D all at once.) So I decided to take 4,000, then 5,000, now 6,000 IU each night. Within 2 -3 weeks I began noticing that the weakness in my calf muscles went completely away. There's a very informative .PDF on Vit D deficiency at:
http://www.savvypatients.com/NEJM%20Vitamin%20D%20Review.pdf. Also, check out the many resources at:
http://www.vitamindcouncil.org/. You can also get the liquid form of Vitamin D that works a lot quicker.
NOTE: That problem resolved with me, but after taking some antibiotics about 1-1/2 years ago, I have been dealing with tight calves ever since. I recently had my blood drawn, and the rhumatologist failed to check for Vitamin D and B-12 levels, so I will have to go to another doctor and ask for certain vitamins and nutrients be checked, some of which are Vitamin D, B-12, magnesium, calcium, and some others.