Have you ever heard Thrice? They are AMAZING for working out. I tend to like harder stuff when I work out, cause it makes me work harder without even realizing it, haha. I will give you some song suggestions that I PROMISE will be so worth listening to because you will seriously fall in love with them. And if you don't like some of them, still listen to the rest cause a lot of them are way different!
Music Box by Thrice (ahhhhh! This one is incredible!)
Whispers in the Dark by Skillet
Chorus of Angels by Haste the Day
For Miles by Thrice
Sihouette by Thrice
Studying Politics by Emery
Stand and Feel Your Worth by Thrice
The Kill by 30 Seconds to Mars
Until the Day I Die by Story of the Year
Casting Such a Thin Shadow by Underoath
Some Will Seek Forgiveness, Others Escape by Underoath
From Yesterday by 30 Seconds to Mars
Wildfire by P.O.D.
And if you want happier, more up beat and not so hard music, here's another list of suggestions for you.
Move Along by All American Rejects
The Adventure by Angels and Airwaves
First Time by Lifehouse
Only One by Yellowcard
The Reason by Hoobastank
Yellow by Coldplay
Light Up The Sky by Yellowcard
Disarray by Lifehouse
Sugar, We're Going Down by Fall Out Boy
If you want any more let me know! There is much more where all this came from.
