i ll have been feeling a nagging pain that comes and goes in the right mid-section of my back, earlier this summer i had the flu virus,was prescribed the z-pack,but lately i still feel tired,and my breathing feels a little uncomfortable,it s almost as i can taste a gases flavor.
Hi I am Chat Doctor. .  In my opinion i think your viral infection still not completely cured causing your flu breathing problem and thus causing the metallic gases flavor. Your back pain could be a kind of muscular spasm treated by painkillers when needed, hot massages with topical gels, muscle relaxants, avoid heavy lifting and vigorous movements with some bed rest will be enough.  For now I suggest some nasal steaming with minor medications as viral infections doesn't need antibiotics, Z pack, paracetamol, antihistamines for your flu. If your back pain persists visit your physician for proper evaluation of the underlying cause. Please click THANK YOU and consider a 5-star rating with some positive feedback if the information was helpful. Hope the above information helps you, Any further clarifications feel free to ask.