Have a cough over 3 months, with a lot mucus I tried many syrups n med no help, I get this cough in fall season between month oct to feb, please help?

Cough. For diagnostic and recommendations , we have to be clear about allergies, smoking, chest x/r .If chest x/r is negative, found out allergy status. If patient smoke, stop .Physical examination ent, and for some blood test looking for ige, cbc.Others as needed, .A cough present for more than 10 to 15 days , have to be check. A virus, could be the first reason , but more than 10 days, check up.
Allergy. This could be seasonal allergies. There are few options for you. Evaluation is 3-4 weeks at a time because we need to see how you respond to the medication.
Bronchospasm... This seasonal cough is likely due to allergic bronchospasm. The treatment for this includes a bronchodilator as well as a steroid inhaler that you would take during these months to keep the cough under control. See your doctor so this treatment can be instituted.
Inventory house. Since you are getting symptoms between oct and feb, I have to assume there may be something in your house that's causing your problem. Check your heating syste for dust, humidifier for mold if you have a basement and its damp consider mold. After doing an invehpntory of your house you may want to check eith an allergist for more help.