In night have sore throat, blocked nose, fever, then go cold, and day time have chesty throat instead when cough headache , feel slightly sick? cure?

Possible sinusitis: and reactive airway disease, causing such symptoms. You need to see your doctor for treatment, you may very well need an antibiotic and other prescription medicines, good luck

Likely a virus : Likely a virus. Take rest, drink plenty fluids, & chicken noodle soup. You should be improving in 2-3 days & healed by 5-7 days. If worsening symptoms persist, esp with fever, then you must see clinician & may need antibiotics. Virus germs don't respond to antibiotics , only bacterial germs, & yours is most likely a virus. Hope that helps.