It is very common for severe coughing to strain your abdominal muscles, causing stomach pain. Since Coughex and Ascoril have not provided relief, and you are noticing brown sputum, it is highly recommended that you see a doctor. Brown spit can sometimes indicate a respiratory infection that may require specific prescription treatment, such as antibiotics. In the meantime, please rest and stay well-hydrated with warm liquids to help soothe your throat and loosen mucus. A physician can safely evaluate your chest and prescribe the right generic medication, like a targeted cough suppressant, to help you heal.