Vitamin D is an important vitamin that our bodies need in order to maintain strong bones, and it is important to discuss your concern with your doctors
">primary care doctor. Without sufficient vitamin D in our diets, we can become predisposed to have low bone density which can lead to osteoporosis and fractures in the more advanced cases. Building healthy bones when we are young is especially important, since the effects of low bone density and fracture
risk usually do not manifest until old age. This is why maintaining a good dietary supply of vitamin D through childhood and adulthood is so important.
That being said, your vitamin D level, although low, is not dramatically so. Most doctors would treat this level of vitamin D deficiency with just a daily supplement, although you should of course check with your primary care doctor (or which ever doctor ordered this test) to see what they recommend in your case.
Other than its effects on bone health, vitamin D deficiency is usually asymptomatic, so it is extremely unlikely that the burning sensation in your muscles with exercise is related to this. I would suggest discussing this symptom with your primary care doctor as well to see what they might recommend in terms of treatment or workup, if necessary.