Is there a reason most mountain ranges seem to run parallel to coastlines?
Mountain ranges are usually formed as orogeny where tectonic plates collides, known as convergent boundaries.

The continental plates have less density than the oceanic plates and the buoyancy results in that they are mostly above sea level. Continental sea floor is known as continental shelf, but usually, it doesn't reach far from the coastline. Therefor the continental-oceanic boundaries often runs sub-parallel to the coastlines we see today.

At convergent boundaries where oceanic crust and continental crust collides, the mountain ranges can therefor form right at the coastline. Vulcanism is also important in the process as volcanoes forms where oceanic crust is subducted under the continental plates. 



Some of the mountain ranges that today are located far from the coast, e.g. the Urals are formed from earlier convergent boundaries between continental plates that today are incorporated in larger plates. 

Convergent boundaries explains most of the mountain ranges (e.g the Andes, Himalaya, the Alps, Nihon Arupusu) but there are however some curious exceptions, e.g. the Scandinavian Mountains that are not located near any convergent boundary and might be the result of regional uplift. However, there is an interesting ongoing discussion on how these processes work.



This is a simplified answer that I hope inspire to further studies in tectonic and geology.