14Muscle Stiffness
Another symptom that many causes of mononucleosis report is muscle stiffness. This condition occurs when the muscles become tighter than usual, making it more challenging to move around, particularly after sleep or rest. At the same time, you can experience discomfort, cramping, and pain in the affected muscles. Keep in mind that muscle stiffness is different from muscle spasticity and rigidity. In these two conditions, you cannot move when the muscles are stiff. Regular stretching and exercise can help relieve the sign. However, medical attention is needed to treat the underlying cause. [14]













