Hi and welcome.
This can be related to pps especially the new weakness but the pain seems to be of neuro-muscular in origin. It sounds like you have developed severe muscular spasm during exercise that is causing pain. Other possibility is nerve impingement which also cause weakness along with pain. I would recommend you to take ibuprofen one tablet thrice a day and apply capsaicin cream over the painful area. Warm compresses can help relieve spasm. However it would be best to get yourself examined by your doctor as new weakness is concerning.
Let me know if you have further questions.
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Wish you good health.