The table I was on just broke and this is my 3rd hand at the new table. >300 BB effective stacks.

3 limpers and we are in the SB with and make it $14, button calls...flop is ...we make it $30 and the button raises to $90... we should normally...?

I think you have to raise in this spot. You have to hope he puts you on the flush draw and shoves. I don't think calling gets the money in enough. In position I might just call but if you smooth call here and lead out the turn it looks very strong. But you would have to lead the turn because if you check the turn he might check behind and its unlikely much is getting in on the river if that happens.

I 3bet to $240 and he tanks..a full minute passed and he puts his hands on the table around his chips like he is going to shove. This looked like a move to gain some info. because he was looking at me for some type of response. Someone at the table shouts out "ask him if he wants action?" He doesn't say anything but motions like he is going to shove again. This went on for another minute and I really thought we had him. He finally sat back in his chair said "fold" and mucked his face up. The entire time he was going through all of his motions I just concentrated on the back of my cards. What else might we have done to provoke a shove?

Should I have made it $20ish pre-flop?

you shoulda reacted to the mock shove like you were bluffing, back in the day I used to convince myself I had like bottom pair or something in this scenario and look/act accordingly. lol@ him though for making himself look like a moron though.