I have to clear my throat often. is this due to allergies?

Possibly: Allergies can certainly give you that feeling, but so can acid reflux(heartburn). This needs to be evaluated, so i would start with your primary care physician.

Possibly: Throat clearing can be a symptom of allergy, but other disease states can trigger it as well. Other possible triggers include chronic sinusitis, reflux, or motor tics. I recommend being evaluated by you doctor or an allergist to determine the cause.