I am a 24 year old female who was recently diagnosed with Inappropriate Sinus Tachycardia. I have been on 100 mg of Toprol XL for about one month now. My symptoms were major exercise intolerance, high resting heart rate and spells of tachycardia, fatigue, shortness of breath, profuse sweating, dizziness and blackout spells. The medicine seems to help more than any other I have been on. However, I am wondering about its side effects. Just recently (about the same time that I started the med), I found a lump under my left armpit. It seems to be a gland or something. Not only was it swollen, but it was sore to touch. Since I found it, it has disappeared and appeared off and on. The glands in my shoulder area have also been swollen. I am wondering if this has anything to do with my body adjusting to the medicine, or if I should consult a doctor. I understand that infections can sometimes cause your glands to swell. Also, should the Toprol help control the perspiration? I have found no relief and am tired of the embarrassment and even more tired of sweating through my clothes on a daily basis. Please help!