Every good thing in your life comes at a price. You may not see it yet, but there are no freebies. If you want a fitness habit, you need to pay for it with time and effort. There are no magic solutions. You simply need to force yourself to suffer. Embrace the pain. If you're not feeling like you're dying, you're doing it wrong.
Go do 10 push-ups right now. Get up from your chair and do them. There is nothing really stopping you. Only the excuses you make for yourself.