Should I take synthyroid?

Hi I am a 16 year old boy, and I when I went to the doctor when I was about 15 and 1/2, I was having trouble sleeping and hadnt slept in over a week. To my suprise I was actually hypothyroid, and had a moderatly enlarged goiter ( my thyroid levels were half what they should be). Now this is where it gets weird. I went back to the doctor a few weeks later, and my levels were in the normal range, still on the lower end of it, but normal none the less. I went into the doctor about 4 more times, each time spaced out by a few weeks or a month, and every time My levels showed I Wasn't hypothyroid, but I still had a goiter. I even went in for that one scan where you take the radioactive iodine and they scan you, and my iodine intake was normal. I just went back in to the doctor yestarday, and he says That I still have a goiter, and told me to started me on synthyroid, 50 mcg dose. Now I've heard a lot of stories from people who say that synthyroid only worsened their symptoms, and I am afraid that this will happen to me to, as I am not even hypothyroid technically, I just have a goiter. So do you think that I should start taking synthyroid medication or not?
Thank you