There's actually a significant difference between tightness and stiffness but what is that difference and what does it mean when it comes the time for your headaches and migraines ? 

People will always say “I'm really tight,I feel really tight through my neck, I feel really tight in through my shoulders” And a lot of people will have had a lot of massages or do a lot of self-relief. They'll use heat packs, they'll use spiky balls, they'll use foam rollers and yet they still feel tight. There's absolutely nothing wrong with doing these things. You want to keep your muscle tension really soft and you don't want to be tight, but why do you still feel tight even though you've done these things again and again? 

Well tightness refers to muscles. When muscles get tight, they're in a shortened state or alternatively they can actually be elongated. They're always being tugged so you feel tight. With that, you would do things like get massaged,  use a heat...