Stiff neck, shortness of breath & why this drill anyway?

Hi all, I'm an older swimmer, just getting back after a 43 yr layoff, and way out of shape (won't go into why). Anyway, the other day, the coach had us doing a drill in which we were to glide with our arms, holding each out (the glide part) while counting to two before continuing the stroke and doing the same with the other arm. We were to kick, same as usual. At one point, she had us hold our heads straight up out of the water when it came time to breathe rather than turn to the side the usual way. I found it impossible to hold my head up high enough, due to stiffness in that part of the spine, I think, to be out of the water enough to take a breath. Anyway, I have two questions. First of all, what do you think is the purpose of this drill, and is there any exercise that will help to get my neck muscles limber enough to bend my head straight back so that I can do this exercise correctly? To compensate for the stiffness, I was having to bring my whole body out of the water in order not to drown! Haha! Does anyone have a website to recommend that explains the purpose of all the drills? Also, where could I find something about stretches and warm-ups? My biggest problem is getting too short of breath early during practice, but if I go too long, I start to feel better in the water toward the end of an hour of hard working out, but the next day or two, I'm too exhausted to do anything. I'm thinking that perhaps I should go back to working out on my own for a while for maybe 30 minutes at a stretch. just swimming, just until I can keep up with these "kids" the whole practice session without ruining the rest of my life. is that I only have so much time, and on my own when I'm able to go, I don't want to get stuck waiting for a lane to be open which is what often happens when I'm not with the "team" which has a set time for practice. Anyone else have this problem? I'm afraid that my occasional stops will interfere with the faster swimmers in my lane or possibly even cause a collision. In reality, I have to discipline myself NOT to swim too long at a workout because I love the way I feel at the time. Any ideas to prevent the exhaustion from some of you late bloomers out there? Surely I'm not the only one to experience this. I don't remember ever being tired but a few minutes after a workout when I was in my teens. The soreness I would expect, however, but I didn't experience that that recall, even when I competed back then, which may be unusual, even at that young age. Thanks for reading all this. Sincerely, Fins Any ideas on all this would certainly be welcome.