This is purely a philosophical question: What is boredom and what causes it?
Boredom is the lack of internal or external stimulation in one's life, but is easily controllable. Lack of stimulus doesn't necessarily mean one is bored, however. There is always an unhappiness component involved at that lack of stimulation. Boredom is controllable because if you're happy with the lack of stimulation, this is the end of the problem. If one makes the decision to be happy and accepting of the boredom, this ends the boredom and paves the way to possibly having a life!
People live their whole lives trying to get extra internal stimulus out of their mind. Others seek to rid themselves of external stressors that hold their peace hostage, both these types of people don't have to rid themselves of boredom, but that may be the underlying result if they change their lives because they may not be settled with the results. Internal stillness seekers should seek peace; externally driven stillness seekers need to try to be happy with their results.
Boredom is also an itchy, angst-ridden want or need to fill up time with value. This is mostly intrinsic, but doesn't necessarily mean someone doesn't have a lot going on in their life. It could be the reason for most of society's ills due to the monotony of existence. Depression is then dealt as the scapegoat for boredom and if these supposed 'symptoms' persist, then antidepressants are thrown in, and that's just depressing.
Boredom, if left unchecked, can harvest fear or fear of the unknown, and can turn an otherwise normal person into an agoraphobe, not wanting to leave the house, etc.
One sits with this problem for a while and if one wants to solve it constructively, one has to promptly create a vacancy in their life; a want for some sort of hobby to fulfill themselves so they can have any sort of achievement of purpose at the end of the day, whether it be running, cycling, video games, building something, learning something, getting immersed in a culture, etc. Human nature has a need to unwind with a mindless activity they can pursue so their subconscious can process other feelings in their life.
Boredom also stems from a lack of escaping sufficiently often enough. In our society of consumerism we have a lack of fulfillment in acquiring more 'things'. In this type of lifestyle someone has discovered the need to shop or be in a place with ambiance to feel fulfilled, or they are continually bored; this is and can be a compulsive need or addiction to seeking something new and exciting outside themselves. Newer and more exciting needs to be just around the corner, or life is boring!
For these types of people, which is the majority of American society, seeking internal happiness is essential. Meditation, is the answer. Fulfillment results from wonderment that we are alive and walk this earth. Happiness in the not doing takes skill that most Americans don't have yet. Gratitude in events or thoughts that don't relate to acquiring or doing 'things' is the answer to boredom.