HELP! Muffins don't rise

You mention that you "get a nice dome", so surely that means they're rising? They look risen in the photo, too. What more are you looking for?

also seem to be baked in deeper pans than yours, if I'm not mistaken. Dunno what recipe you are using but if you add maybe a tiny bit more leavening and  little more liquid then the domes will spread over the edges of each depression and increase in volume. The height of the muffin bottom is totally dependent on that of the pan though, the underside of the domes will never rise above the top of the tray if that's what you are expecting. Also I notice the underside of your muffins look kinda scorched. Maybe that's just shadow in the photo but you can prevent over-browning either by baking on a higher rack, a separate baking sheet, or by both greasing and flouring your pan. Adding salt into that flour and using salted butter as well will also help.

I've found that mini fluted muffin pans such as Wilton's provide superior results, in that the inside portion cooks all the way through. But they are not for making huge muffins, just pretty ones.

The muffins do look like they have risen. Are you using whole grain? Because that would make the muffin more dense. There are a few things you can do for fluffier muffins. As andychrist suggested, you could try increasing the amount of leavening a tiny bit. Also make sure it is fresh. You can also try using paper liners. The rising dough might be able to cling to that better as it rises up.

I have made a lot of muffins in my time and I would be happy with what you got.  If you are after height you need to make the mix a little dryer, if you want them to spread more you need it wetter.  The other thing I find is that most recipes say nothing about letting the muffins rest before baking but in my experience leaving them at least a half hour between  scooping and baking gives better results.  If you have inclusions like raisins or dates if you wash and soak them for an hour or two prior to use you have better results.  There are commercially available pans that have an indentation for the muffin top, you can overfill these pans and get much larger tops than normal.  

Here is a photo of such a tin

Gerhard

Ur Muffins Look Fine But If U Over Mix ur Batter U Will Get A tougher Product And Affect The Rise batter Should B Lumpy 

I second all the other suggestions.  Freshness of your baking soda or powder might be a culprit: http://www.thekitchn.com/how-to-test-if-baking-soda-or-baking-powder-is-expired-tips-from-the-kitchn-111759