It sounds like a swim bladder issue (not disease) the duct between the swim bladder and stomach may be plugged, swollen, inflamed or infected or a combination.
The espom salt 1tsp/gal along with daily 100% water changes with Epsom salt water for 10 days along with a fast can help these symptoms, however, if it is an advanced infection you may need to use a broad spectrum antibiotic, I don't use OTC medication so I can not recommend any