Hello, You are suffering from swelling along the left side of your cervical spine. Your neck gets stiff when the swelling is larger. The swelling is hard and has gone down on taking prescription medicine Fludrocort by your treating doctor. You have not mentioned the reports of the carotid and thyroid ultrasounds. You are suggested to get clinically examined by a GP / oncologist. Treatment depends on the actual cause of the neck stiffness and swelling. Get X-ray, CT, MRI, Electromyography, biopsy (in case of tumors, swollen lymph nodes, lymphoma, etc.), spinal tap if required. You will be treated accordingly with physical therapy, manipulative therapy, medications, and surgical repair (if required). Low-impact exercises and walking may help relieve stiffness in the neck by improving circulation to soft tissues, resulting in easier healing. Get connected with a physical therapist. Exercises will have to be done slowly and with caution. Your breathing should be synchronized with each movement. Do not do the exercises absent-mindedly or with less focus. Your treating doctor will detect the cause (pathology) and then treatment may include corticosteroid injections, antibiotics to control infections, muscle relaxants, etc. If malignancy is detected you will be recommended a combination of conservative treatment, radiation therapy, etc. Get diagnosed and treated at the earliest. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Nupur K., General & Family Physician