A:
No, high blood sugar does not directly cause muscle pain.
However, there are connections between diabetes (a condition characterized by high blood sugar) and muscle pain.
For reasons that are not entirely clear, people with diabetes are prone to shoulder tendonitis. Because the nerves supplying the shoulder tendons also supply nearby muscles, the pain is often felt in the muscles. This is an example of "referred pain," when pain is felt in one place (the muscles) even though the problem arises in another (the tendons).
Another situation in which people with diabetes develop muscle pain is a condition called diabetic myonecrosis. Diabetes tends to damage small blood vessels. Occasionally, a small artery supplying a muscle (such as a muscle in the thigh) becomes blocked. The interrupted blood supply to the muscle causes muscle death (myonecrosis), an extremely painful condition. It's not clear why some people with diabetes develop this condition while others do not. It's possible that good, long-term treatment of diabetes might prevent it.
Finally, people with diabetes commonly develop nerve disease (neuropathy). That can lead to muscle weakness. However, muscle pain is not a common complaint among people with diabetic neuropathy.
In each of these conditions, it's the diabetes (or its complications), not the high blood sugar, that causes muscle trouble. People with diabetes may have variations in blood sugar over the course of the day but there is not clear link between periods of time when the blood sugar is high and symptoms of muscle pain.