I have a sinus infection and chest infection i've been on amoxicillin for two days now and feel no better and i keep coughing mucus up?

Continue therapy: A sinus infection can also be chronic, I highly recommend you to finish the course of antibiotics first. It's little early to see improvements after couple days

Sinus infection: Antibiotic treatment should extend for a minimum of days and 14 days is not uncommon. The mucous is normal and ask your pharmacist to recommend a good expectorant.I think you will need at least 10 full days of therapy.