I’m telling you to work on your pelvic floor. You may not even know it’s tight. If you can do a reverse kegel, which I’m sure you can once you figure out how, your glans should fill up. Then you need to take extra care to relax your pelvic floor throughout the day and practice not clenching during sex or maturation. It will take a while but once you get it, your problem will be solved. It took me about a year to train myself to relax the floor.
Start by either a kneeling position or sitting on the edge of a chair with your legs spread apart which opens up the floor. Another good way to find the muscle is to squat and push out your perinium, taint region. You should feel it shift. Once you identify it you are on the right track. Google male pelvic floor relaxation and you should find plenty of info.