You need to get a detailed medical examination as soon as possible. In an early age like yours, weakening of muscles should be considered as a serious issue. Yoga and massage therapy can be included in your daily routine as this is helpful in easing pain and calming the affected muscles. You can include gooseberries and liquid food in your diet as it helps tightening the weak muscles. I had a similar but different condition in my younger days and maintaining a healthier diet helped a lot. Hope you find this helpful.