Talk to General Physician on Light Fever And Body Pain

Assalam o alaikum, my husband had on and off temperature of 100.2 degrees and body pain yesterday, no cough or loss of smell or taste. Today he was feeling much better with no temperature since morning and no nody pain.

He went to a doctor who took his xray and said he had infection and should isolate himself, no need to take corona teat. My question is, can you tell a person is corona positive through xray or the infection could be something else he should he go for a test.