Cough will often respond to an expectorant like Robitussin. Dextromethorphan is a good cough suppressant, so try a product containing Dextromethorphan. If your cough is severe, you should see a physician. Most sore throats are not caused by strep. Strep may not be a particularly sore throat.
Sore throats caused by a virus can be very painful.
A rash is rare with sinusitis. If it persists more than 24 hours, you should see a physician. Yellow, green, or rust colored nasal discharge. Headache or a sense of pressure over the sinuses. Swelling or heat over a sinus.