Calf pain question, can anyone give me an answer?

I'm currently 22 (female). When I was 18 I had arthroscopic knee surgery, and it resulted in a DVT. I took Lovenox and Coumadin, and it eventually went away. In the process of figuring that out they told me I have reflux in my veins which is an early sign of varicose veins apparently? I am an athlete and since then I've always had issues with that calf cramping, or feeling like it's pulled/strained. It's always the first muscle to get sore/pulled when I work out. When it's strained and I'm sitting down it often feels like there are air bubble moving through it, it's a strange sensation, and it's very sensitive to the touch obviously. I just didn't know if anyone can explain why it's like that or if its anything I should be concerned about, more than just a sore muscle (I'm used to those). I'm also about to undergo ankle surgery on the same leg in about a month, and they're aware of my DVT history and everything. It is just a little nervewrecking, wondering if anyone could make some sense of it?? Thanks!