bacterial infection
"Let me just say this about this medicine. DO NOT LIE DOWN FOR AT LEAST 20-40 MINUTES AFTER TAKING DOSE! I just did like a half hour ago and I am regretting it.  

I started taking the Clinamycin for a very nasty, very large abscess that took up a huge portion of the roof of my mouth.  The infection started in the tooth to the right of my right front tooth.  The pain was UNBEARABLE.  I've been taking the medicine since Wednesday night (5 days ago) and I haven't had the problems that I've had with Penicillin (nausea, twitching, hunger pains that don't stop). But I ignored the warning and lay down.  So much burning in my chest! I hope it goes away soon.  It's so weird!"