You're worried for no reason! Your symptoms can fluctuate and the fact your breasts aren't as tender anymore is normal.
Also, baby could be in a position where you can't feel him as well, or he's just extra sleepy. A tip to help you if you're worried about movement: drink/eat something and lay down for an hour. If you feel baby start rolling around and moving, everything is A-OK!
Also, when you're up and about, your swaying rocks baby to sleep. And your stomach is pulled taut, making it harder to feel the little one. So sit down and relax and you'll probably feel baby move a little or a lot.
I have never made it to 23 weeks, but my friend JUST had a baby last week....From what she said, the baby definately has more active days than others (just like us)...so I would say that if he doesn't move much one day, it's not a problem....Her's sometimes only wiggled once a day and other days you could literally see feet on her belly.....Breast tenderness - From what I've read (and I've read ALOT on pregnancy), it's normal for alot of the pregnancy symptoms to subside...sometimes after the first trimester or even later (which must be your case)....You just had an appt. and I'm assuming that they said everything was OK....so sit back an enjoy! Lots of luck to you!
What you are experiencing is completely normal! I have been going through the same things. I will be 26 weeks tomorrow and my breasts actually flucuate in tenderness still. Somedays they are sore, others, they are fine. Just the other day I was worried because the baby hardly moved at all...the past 2 days it's been non-stop movement! =) I think the baby was growing or just really tired that day. =)