Teething/ Solids/ Fussing

I think Ren is teething, but I have no idea. It looks like he has two white spots on his lower gum. They have both been so fussy these last couple of days. I wondered if it was time to start solids. Maybe they are getting hungry? I started rice cereal. It did not go so good. This week I started some carrots. That didn't go good either. I bought some baby food from Whole Foods that was for 4 months and up. Well they won't even open their mouth. So I figure they aren't ready yet. So back to square one. What is all the fussing about??