Can implantation occur 6 days after ovulation? Are tender boobs a result of this? Positive pregnant test 17 days later so not pms. Implanted sooner?

Perhaps. There's no guarantee that you ovulated on the exact day that you think. A 28d cycle with ovulation on d14 is only the average. So, if you ovulated on day 15-16, then that could offset implantation, which is about 3 days after ovulation.