Sore breasts after Chemical

Sweety

I had early chemical couple of days back (got faint positive on 8 dpo and the test line became lighter each day and bfn on 11dpo). I am 12 dpo now and having sore breasts from yesterday evening. Didn’t have sore breasts when I got faint positives but they were tender to touch. Any idea why I’m having sore breasts after chemical?