YYYY@YYYY I am wondering if I have any type of flu virus. Tuesday and Wednesday I threw up.   That is over now but since then I have had a stabbing pain in one side of my back just above my waist. Its been a consistent pain, the first day was throbbing, and now its more  Of a dull throbbing.
It just looks to be a case of muscle pull post violent vomiting. Back pain is common after vomiting as back acts as a support and stabilizing structure for the body and can easily get strained or injured during sudden violent movements, which sometimes may happen during vomiting or sneezing. I would recommend applying ice packs at the site of pain and some over the counter painkillers like Acetaminophen. It is unlikely to be a flu as there are no other symptoms suggestive of flu are present like cold, fever, generalized body ache. Hope this answers your question, Thank you.