I read your question carefully and I m sorry for the pain you re experiencing. Headaches can have many different causes, but in your case your mentioning green mucus makes me suspect sinusitis as the main reason. Sinusitis means infection of the sinuses which are some cavities inside your facial bones which open into your nose cavity, so the green discharge might come from them. While for the moment you could take some over the counter analgesics for your pain (like Ibuprofene) you should be checked by a doctor because if the diagnosis is performed by the exam and the necessary imaging tests you might need more specific treatment with decongestants (drugs easing the elimination of the secretions) and perhaps antibiotics. Hope to have been of some help to you. Feel free to come back here to ask further questions about this or any other health issue. Me or my fellow colleagues will assist you to the best of our possibilities.