Hello dear teacher and thank you for being part of our virtual clinic! 1. Have you had a full blood test? Low iron, magnesium and potassium can cause aching, cramping feelings in muscles, and also make you feel tired. So can out of balance hormones. 2. It might also be worth keeping a food diary to see if there are any foods that trigger the symptoms (or ease the symptoms). 3. Common causes of leg stiffness or tightness are fibromyalgia (signs and symptoms include deep muscle pain, painful tender points, and morning stiffness, sleep problems, fatigue, and anxiety), multiple sclerosis, sprain or strain, and hyperlipidemia If I were your family doctor I would advise you to receive radio graphic imaging procedure, complete blood count, plain x-ray, kidney function tests, glucose measurement, electrolytes panel Your all day up posture may be the main cause, and maybe you are perfectly healthy, but we have to have facts before saying so! Hope to have helped, write to us again for further info! Take care and all the best, doctor Juna!