Hi about two weeks ago i had the worst sore throat, i woke up 3 days later i could not swallow my throat was painful i had to take pain killers ?

Many causes: Such a severe throat to the point of being unable or very painful to swallow can be strep, mononucleosis, or "cold sores" in your throat. Since you don't describe any symptoms now, I would expect it was these or another virus. There is little you can do to keep it from happening again, except avoiding those that are ill, always wash your hands after touching your or others' eyes, mouth, nose.

Acute Pharyngitis: You may have had an acute infection of your throat, possibly involving your tonsil (if you still have them). The infection could have progresed to become severe enough to cause very painful swallowing. If this is happen frequently you should be checked by your primary care doctor for the various causes of sore throats.