My apologies for skimming over the posts, I hope no ones already said this but could it be drag issues, I know when I changed lines on my bait rods, to lighter, I had the same issue with mono, it would just rats nest horribly, too much line at once, so I had to fiddle with the drag.
I use an Abu Garcia 6500 c3 Ambassador.
On my reel there are 2 (3 - but the 3rd only changes it from silent to that annoying click when reeling or when somethings pulling hard enough to drag line out) things that affect the drag; the 5 point star (god I love my technical terminology) and beside it there is a small dial, the small dial affects the drag out when the lines unlocked, ie a cast, and the 5 pt star ... thing. sigh, hah! affects the locked drag ie, fish on.
BOTH have to be adjusted properly, they'll completely change how you cast, in fact you'll actually gain more distance with less effort. When its configured correctly. I noticed it, when I went from fishing small rivers like coq & vedder to bigger ones like stave and fraser.