Mucinex Rapid+Clear Pain Headache and Mucus Congestion 16 Liquid Gels When cold and flu symptoms like body pain, headache, and thick mucus congestion strike, reach for Maximum Strength Mucinex Rapid Clear Pain, Headache, & Mucus Congestion Liquid Gels. The rapid release liquid gels help relieve cold and flu symptoms so you can get back to your day.