Hi, Based on the symptoms you described, it is important to consult with a medical professional as soon as possible. The fullness in his stomach, constipation, and light-headedness could be related to a number of issues, such as digestive problems, dehydration, or low blood pressure. The pain at the base of his skull and neck cracking could be related to muscle tension, but it could also be related to other conditions such as arthritis, disc problems in the neck, or nerve-related issues. Given that your husband has a history of a titanium mitral valve, it is important to inform the medical professional of this as well, as this could be related to his symptoms. It is also worth noting that some of the symptoms you described can be indicative of serious medical issues, such as a stroke or heart attack. Therefore, seek medical attention in time. I would recommend making an appointment with your primary care physician or urgent care center as soon as possible. They will be able to conduct a physical examination and may order additional tests or refer you to a specialist if necessary. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Diwashish Biswas, Internal Medicine Specialist