My boyfriend read my message but didn't reply? Help?

2 days ago my boyfriend & I were talking normally then when I asked 'How was your day?', he left it on read and didn't respond but he was on twitter tweeting, retweeting and liking stuff etc. So yesterday I decided to tell him 'So you can't reply. Ok then' he also read that and didn't respond.
Today I decided I'm not gonna message him again cause I'm not going to chase anyone. I must have retweeted some indrects on twitter and then he messaged me saying 'Yo'. I said this 'Lol so you left me on read? How come?' and he said 'I apologise' then I responded saying 'Mhm' basically being dry. He read that and hasn't responded but is on social media and stuff. Why is he doing this?
My boyfriend read my message but didn't reply? Help?
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