All great advice, I prefer low angle for touring for a number of reasons a) to avoid paddle blade being caught by wind and b)if your where to adopted a high angle paddle stroke as used in racing or white water you will be effectively lifting the paddle like a weight lifter thousands of times during a few hours of paddling.
A whole lot of wasted energy, low angle means less lifting. A lot of paddlers over do it with paddling cadence. When you get a chance team up with a friend of equal paddling skill. Both set off side by side only you will be paddling a half the cadence of your mate but with full long stokes from toe to hip and good body rotation (your torso is like a spring wind it up feel the tension and unwind) you will find you caver the same distance in similar time.
Your kayak will only go so fast don't force it. As you paddle your kayak a wave forms under your hull (see bulge hull boats)which it sits on, if you paddle to hard you will try to ride up over the wave, effectively stalling your forward momentum.
It is hard to diagnose the problem online without seeing you paddle, the only other suggestion I would make is to look at the feather of your paddle. I have seen many a paddle suffering from carpel tunnel due to using a paddle with a 90degree off set. Get a quick lock of smartshaft so you may addust the angle.
When working with clients I always try to get them to adopt a low angle stoke, wind up un-wind (the torso) toe to hip, long, low and wide, think like a butterfly or a ballerina gently, gently. The Zen of kayaking: Think not that you are pulling your paddle past your kayak, but rather that you are pulling your kayak past your paddle! Hope this helps