Hi, I Went On The Implant Birth Control Back In

Hi, I went on the implant birth control back in April. No side effects and period went away as soon as I got it. I have a boyfriend who I am quite active with. A couple weeks ago my boobs were so sore for over a week. That went away. Now my nipples are beyond sore, I can't even touch them. I never usually have that. I was on depo shot before this and only had it when I was coming off it. Is it a side effect?