Hi.. Welcome to HEALTHCARE MAGIC.. As per your complain such a severe pain that lasts for about 15 minutes that seems to be episodic pain seems to be most probably due to nerve related pain.. In case if it is due to sinuses it can be due to sinus infection or inflammation leading to Sinusitis.. It would however be associated with other symptoms of Sinusitis along with pain.. Trigeminal Neuralgia that is a disorder of Trigeminal neuralgia which is also known as nerve of face can be a cause for such a severe pain.. You need to consult a Neurophysician and get evaluated for the exact cause of the pain by getting an MRI done as there can be some causes like the most common one is a large artery impinging over the nerve causing damage of the Myelin Sheath [ a protective cover over the nerve] leading to severe electric shock like pain.. Other causes are disorders like Multiple sclerosis, tumour compressing the nerve, physical trauma etc.. The common drugs given to relieve neurotic pain are Carbamazipine that is the first line drug while others like Gabapaentin, baclofen, oxycarbazipine etc but in case if the pain does not subside then surgical procedures like Microvascular decompression in which the compression over the artery is surgically removed is done.. Other procedures like Balloon decompression,gama knife radiosurgery, glycerol injection etc can be done to relieve pain.. Hope this helps.. Regards