How Can severe Fever Along With Body Pain Be Treated?

My husband has flu like symptoms. He was at urgent care today with a temp of 100 and extreme body aches, especially in his back and chest area. His vitals were normal this morning except the temp. A chest X-ray came back clear and a nasal swab for Infuenza came back negative. The doctor told us there is a virus around here that has very similar symptoms to influenza and he assumes that what s going on here. He has been taking tylenol for the pain but it s not working very well. The biggest issue is that it hurts him to breath so he is breathing faster and more shallow than normal. When he lays down to sleep, his breathing gets a little slower but because its not a full breath, he wakes up almost gasping for air. What do you think? Do we need to head to the ER?