Went into a walk n clinic to get checked & the doctor there ran a blood test call fedrate & said i don't have temporal arthritis what's causes my pain?

Need for examination: It is not feasible to provide an answer without taking history, doing a physical examination and may be lab tests and imaging.

What symptoms?: First of all, a 20 year old will never have temporal arteritis. It is rarely seen under the age of 60. Secondly, you don't mention where your pain is so i cannot answer your question. If it is headaches, and they are sudden in onset, then you need evaluation including a ct scan or MRI of the head.