You feel fine all day, but something happens when you lie down. You end up with this irritating tickle in your throat or a nagging cough that only happens at night. It's been like this for weeks so what gives? According to Shape, here are five reasons you may be coughing:

• Asthma: I know when most people think of asthma, they think of someone gasping for air. Although this can definitely be a symptom, most people with asthma more commonly experience a dry cough, so you may want to see your doctor to get tested, just to make sure.
• Sinusitis: If it's not asthma, a chronic stuffy nose could be the culprit. When your sinuses are clogged with mucus, it can drip down the back of your throat (post nasal drip), and cause that annoying tickle. Allergies may be causing your sinusitis, so your doc may prescribe allergy meds or a nasal spray to help clear the way.

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• Check your drugs: If you're taking certain meds such as ACE inhibitors for high blood pressure, a dry cough could be a side effect. So ask your pharmacist if coughing could be caused by one of the medications you're on.
• Acid reflux: If it's not asthma or sinusitis, another medical condition that could cause coughing at night is acid reflux disease. When you lie down, the acid in your stomach that causes indigestion and heartburn can also wash into your lungs. If you think this is the problem, try to eat a smaller dinner earlier in the evening, and elevate your head at least six inches when you sleep. If this doesn't help, there are OTC medications that can do wonders.
• Iron Deficiency: Your cough may have something to do with your diet. If your body is low in iron, swelling and irritation in the back of your throat could be a symptom, which would make you cough. If this sounds familiar, an iron supplement may be all you need.

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