Hello, In standing or walking position the peroneal brevis tendon normally does not gets stretched so you do not get the pain. The tendon gets stressed up while in sitting or similar position due to injury arising out of longitudinal split. You need to give as much rest to your tendon and muscle so that it heals quick. Once healed you will not get pain sitting in position. When you rest try to keep your full right leg stretched out. This will give your more relief. You can take pain relieving medicines (Combiflam or Naproxen, one SOS when needed) if you are in much discomfort. It does not look like peroneal nerve damage. However, you are suggested to not take unnecessary strain or stress. You can try orthotics, braces or foot splints that fit inside the person s shoe, can bring relief. But avoid it if you are not comfortable in it. Some injuries take a longer time to heal, have patience. You can try Peroneal nerve test to see if there is any injury. If you have problem or weakness in foot eversion (SPN) and foot / toe dorsiflexion (DPN) then it may be indicative of peroneal nerve injury. Nerve injuries take longer time to heal. Get 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