Hi grny,
You are having acute pharyngitis, you can try with antibiotics (like augmentin), povidone iodine throat gargles and drink plenty of warm water, and this should reduce your sore throat. If you are having acidity/ reflux please do take medicines to reduce your acidity and avoid coffee/tea and fizzy drinks for few days. Hope this would reduce your symptoms.
Regards
OHNS2010
Sounds like nasal/sinus drainage irritating your throat when you are lying. Are you coughing at night?