Why am I having pain in my left eya and neck ?

see u need to look out ur posture in sitting esp at work .table shud be at agud height and char shud be comfortable and stretchable when needed .if u r using computer screens ,eyes shud be in level with it..... Also get ur digital neck xray done to rule out cervical sponylitis ....tell us the report ofx ray...ALSO GO FOR regular neck and back exercises .. As far as block nose is concerned ..many people hav deviated nasal septum which often causes sinusitis ..which may be a reason for pain and watering in eyes....u can start respiratory yogic exercises like kapalbhati and anulom vilom regularly ...these will certainly benefit if such is the problem but it takes 3-4 weeks.