Hi, I'd like to help you with your question.
It sounds like you may be depressed. Although I do agree with you that being punished as a child by having to clean would cause you to see it as something to dislike intensely, your feelings seem to go beyond just disliking chores.
You are living with constant pain and have PTSD, which includes feelings of depression and hopelessness. You may not have enough symptoms for a depression diagnosis, but it is worth being evaluated by your therapist/doctor.
ADHD can also cause difficulty with motivation, as can changes in your life or overwhelming expectations. Alcohol and drug use can also affect mood and therefore motivation.
Taking steps to overcome your lack of motivation involve figuring out why you feel as you do then addressing it. So for example, if you feel you may be depressed, therapy and/or medication may help. Support can also make a difference. Also, try making lists of what you need to do then taking only one step at a time. Limit yourself to accomplishing one thing. You may find that when you try to limit yourself, you actually motivate yourself to accomplish your goals.
I hope this has helped you,