I am so sorry to hear about your trials with chronic pain at such at very young age! I too, started having chronic pain issues in my early twenties. I am 31 years old now and have been managing chronic pain for over 10 years.
You are taking a lot of oxycodone per day but that is what it takes to keep your pain levels down. I have no doubt that you are NOT a drug addict.
Oxycodone is a great pain medication. However, it works best for breakthrough pain which is pain that is above your baseline pain level. Typically, a long acting opioid is used for pain relief from your baseline pain levels. If pain breaks through the long acting opioid, oxycodone or some other Immediate Release opioid is used to relieve the breakthrough pain.
I used to take only short acting pain medication as well but I found that I was chasing pain all day as the effects wore off so quickly, way before it was time for another dose.
I think you would do much better on a long acting opioid such as MS Contin, Kadian, Fentanyl, or even oxycontin which is oxycodone in extended release form. These medications slowly release the opioid over a 8-12 hour period and in the case of fentanyl, over a 48-72 hour period.
I know how it feels to be chained to prescription medications all day. I know you are tired of having to take so many pills per day and would like some freedom from pain meds while still getting adequate pain relief. So, I think a discussion with your physician about adding a long acting pain medication would be a good discussion to have.
Are you on any other medications other than oxycodone? I have found that the addition of an anti-depressant, anti-convulsant, and muscle relaxer has helped reduce my overall pain levels. This is another good topic to bring up to your physician...are there other non-opioid medications that can boost the effectiveness of the opioid medications.
Tolerance is often reduced through rotation of opioid medications. You may need to switch from oxycodone to hydromorphone or oxymorphone as your body has built a tolerance to the oxycodone. You may be surprised to find just how much less medication you may need from another opioid that is chemically different from oxycodone.
Hope that helps.
I would like to comment that when I said I'm taking 250 - 300 mg oxycodone i meant that for a whole day, and that is on a bad day. Typically I'm anywhere between 150 and 300 mg per day.