I would say that my heart aches for you

But Webster says to ache is to suffer from a cotinuous dull pain

The pain is continuous but it's far from dull

It's more like
A constant tingle in my toes, anxious to leap off the edge and fall with you
A rigidity in my muscles that keeps me from grabbing your waist and pulling you closer
A tossing and turning in my stomach, a stomach that doesn't understand if this feeling is reciprocated butterflies or unrequited nausea

It's more like a burning fire on my lips that can only be extinguished by the ice upon yours

baby, it's far from a dull feeling