Like depression and other emotional stress, bitterness and resentment  can aggravate or cause physical problems such as arthritis. You can be  affected mentally, spiritually, and otherwise. Your relationships will  always suffer.

God can free you from this sin.

"Make every effort to live in peace with all men and to be holy; without  holiness no one will see the Lord. See to it that no one misses the  grace of God and that no bitter root grows up to cause trouble and  defile many" (Hebrews 12:14,15).