Exercising may decrease headaches. It is certainly crucial for weight loss. To get most of the benefits of exercise, you only need to think of exercising in small chunks of time, even 10 or 15 minutes. Most people are able to fit exercise more easily into their lives when thinking this way. We are looking for a total of 30 daily minutes on average. The more the merrier. Some people do well counting total minutes of exercise from Monday to Sunday, including everything (walking, etc.).
Many people get into diet and exercise, for a period of time, and then out of it. Getting back into exercise takes some inertia, such as walking (or a stationary bike) for 5 minutes. Just do something for a few days, and you will get back “into it”. Don’t worry about “going to the club and getting my heart rate up and exercising hard for an hour”. Just dive back in with baby steps.