Is it normal for guys to text randomly? (need your opinions)

So i met a guy at a club.. Ofcourse it's all about fun and all.. He liked how I looked.. So we've been friends and we went out once had casual sex no strings.. However I sort of liked the guy and i told him once and he said nothing at all, I even asked if there's someone else but he said none and it wasnt too late to let go.. So now I went silent as I should,I kinda forgot the dude(no lie).. So like six months later he texted me randomly asking how the sex was like and i answered him..so he always sends random texts even without saying hi like a normal chat should be like cz sometimes you don't know what people are going through so saying hi is important.. Today he texted me asking for my plans tonight and i was at the hospital.. I dint reply.. I don't know why it bothers me that I feel like its care less and a little disrespectful.. Should I tell him that or I should ignore it? It really bothers me..