What does your relationship with money look like?
This is very telling in why you spend/invest the way you do.
If you are prone to "loan" money to those in need but never see your money back or the benefit of giving the money, this could be why you are apprehensive when it's time to invest in yourself/business.
If money is slow in coming to you, it makes sense that you would hesitate to spend money on your business, even though you know you need to, because you need what you have to stay afloat.
If you have witnessed first hand that spending money helps make more money (on marketing for example) then you are are more prone to trickle money where you absolutely need it.
If you have invested money, lost it and invested again to get a bigger increase on your business, you know that investing can be scary but rewarding in the ability to scale your business.
I implore you examine your relationship with money. It shouldn't be the thing that holds your business, or you, back.