Baby has to Suck

My little guy is a bit over 15 weeks and for the past probably four days he's been extremely fussy. Not all of the time but he will start screaming out of nowhere. Most the time he wants to nurse, but not always nutritional nursing, rather just sucking. Sometimes a pacifier will suffice too. When he's got his pacifier, he grabs it and move it then chews on it a bit. We have a couple teether things but he's only interested in like one. Could it be teething causing him to need to suck more, be extra fussy, and scream? What else could make him want to suck all the time? He's fed well, eating well, no fever, pretty much the same diaper habits. He doesn't necessarily seem sick or anything, but he does seem upset and/or uncomfortable at times.