Since we can't see your biomechanics, we will not be able to properly tell you if your fishing the jerkbait correctly. What I can tell you is, if your wrist is just sore without lingering pains or swelling than you may have not developed tendonitis yet. If you have developed these symptoms then you may have developed some tendonitis and you may have to take a break for a week or so and ice with mild stretching. The tendonitis will usually present itself on your elbow most of the time. Hence "fisherman's elbow" aka tennis elbow or lateral epicondylitis. Trust me you don't want that. I personally battled with this for 2 yrs and it can be debilitating. If this technique is new to you, then use the technique for shorts bouts instead of long bouts. Take breaks often. Over time you will develop the endurance. Also you may want to look at your gear and maybe lighten it up or make sure its properly balanced. Lastly, ask a fellow angler that has experience with this technique to evaluate your form and maybe give you some feedback on correcting your technique a bit. Maybe some or all of these factors maybe your culprit. Best of luck, if you are not finding any remedy, send me a PM and I could go into further detail. I am not pulling the information out of the air. My profession and backgound is in Exercise Physiology and I have dealt with these similar types of issues before.