The causes of muscle tightness include overwork, rheumatic diseases, high mental tension, and so on. 1. Overwork: long-term overwork can make the whole body muscles in a tense state, thus feeling the whole body muscle tight. 2. Rheumatic diseases: rheumatoid arthritis, osteoarthritis, etc. can appear muscle spasm and stiffness, especially the affected joints are prone to morning stiffness, which improves significantly after activities. 3. High mental tension: fear, anxiety and other emotions can make the spirit of high tension, so that excessive muscle contraction, spasm, muscle tension rises, the emergence of the symptoms of muscle tightness. Sleeping all over the body muscle tightness may also have other reasons, it is recommended to go to the hospital in a timely manner, improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.