Brief Answer:
It could be DVT, cellulitis or muscle spasm

Detailed Answer:
Hello ma'am
I had gone through your question diligently and i can understand your concern

one sided leg pain could be related to muscle spasm, Deep vein thrombosis, sciatica or nutritional deficiency like calcium and vitamin D deficiency

I would like further information to help you better
have you ever had similar problem in past?
Are having any metabolic disease like diabetes obesity or high blood pressure?
Do you exercise regularly or you are not moving much ?
Is there any swelling in the leg?

Meanwhile you should take pain killer like diclofenac with muscle relaxant like chlorzoxazone combination drugs for symptomatic relief
Physiotherapy is also recommended

waiting for your reply
Follow up.questions are most welcome
Regards

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