Why do we need healing from god?

Answer 1

Because we have this 'sickness' called sin. The Bible refers to sin as a a governing principle or power, that works within people:

Rom 5:12 Sin came into the world through one man, and his sin brought death with it. As a result, death has spread to the whole human race because everyone has sinned.

The healing God gives to those who come to Him in faith is healing from the power and the penalty of sin:

Rom 6:17,18 But thanks be to God! For though at one time you were slaves to sin, you have obeyed with all your heart the truths found in the teaching you received. You were set free from sin and became the slaves of righteousness.

Answer 2

I don't think we do.