Are yellow spots on my skin normal? they are on my upper arm.

Probably not: Normal healthy people do not have yellow spots on the arms. Skin rashes are difficult to describe with words. A rash that is unusual (such as yellow spots), lasts a long time, or keeps recurring needs to be examined by a primary care doctor or a dermatologist (skin doctor). The doctor can start treatment, or he can do additional testing if the diagnosis is uncertain.

Not usually: These lesions would likely need to be examined and more history obtained to be able to provide you with useful input about the diagnosis or possible treatment.