"You got no lungs and you got no legs."

A funny thing happened to me today, at least its funny to me. While I was at the pool during open swim there was this what looked to be highschool team (swam year around) drilling. When I finished my sets the coach who was there approached me and said, "You a swimmer?" I kinda laughed and said "No, not at all." He then looks at me and says, "Well you sure work hard for not being a swimmer." We then discussed that I was a junior in college and he told me I should try out for the swim team. Turns out he coaches highschool and coached college teams around my area and was watching me breifly while I was swimming. As you can see by the title of the thread he pointed out that I have no lungs and I have no legs, which is correct and I have been trying to work on those two attributes for awhile. He went on to say that with a few minor adjustments to my freestyle and with some proper training I could scare some people (I don't know if he was being serious or what but he sure looked it). I haven't been swimming for all that long (about 8 months or so, only being serious for about 5 months) and have never been coach, so I kinda laughed at the idea of me being a college (D3) swimmer. So I come here to ask you fine swimmers how could I improve in these two areas? I know theres the "Help my flutter kick is horrible" thread but I haven't found much on how to increase lung capicity and would like to hear some tricks/drills that may help me breath easier/last longer while swimming. One thing that bothers me as well, whenever I swim a long set (like 100's for me) the back of my neck bothers me. I don't know if it's because I'm not relaxed or because my head is to high but it cramps up sometimes. Sorry for the long winded post, I just thought it was a funny story and would like to share it with you all while asking for advice :)