I've experienced this often. Sounds to me like a sinus infection with post-nasal drip. If you let the symptoms go unchecked, the mucus could go down into your bronchial tube and cause bronchitis, or even into your lungs and give you pnemonia. At least this is what my experience has taught me.
If I were you I would use sudafed or mucinex, and if chloraseptic spray would offer relief for the sore throat, it couldn't hurt.
If things don't get better I always see a ENT doctor who usually puts me on augmentin or amoxicillin, at worst a medrol pack.
Could be a post-nasal drip. Try irrigating your nose with a salt solution.
A test with bronchodilators for 2-3 weeks will be useful to relieve the symptoms.
Other possibilities are central airway obstruction, parenchymal pulmonary disease, gastro esophageal reflux etc.
Treatment with Beta-agonists with or without Cromoglycates and Inhaled glucocorticoids against prescription will help. Proton pump inhibitors can help if acid reflux is suspected. I suggest you to consult physician. Take care and regards.