I had lumpectomy for breast cancer then had to have chemo now drs want me to have radiotherapy I don't want to have anymore treatment should i?

You should. Discuss your concerns with your radiation oncologist. Not have the radiation will increase the chances the cancer will come back.
YES!!! After lumpectomy radiation plays a key role in decreasing the risk of local recurrence in the breast after lumpectomy. This is a seperate effect than that of chemotherapy. Without radiation your local recurrence could be 3-4 times higher. If you fail locally because of foregoing radiation, this may put you at risk for metastatic disease as well. Please talk to your oncologist and finish treatment.
Need radiation tx. As a patient you have the right to refuse any therapy as long as you are aware of the consequencies of your decision. Now, radiation therapy will be needed if you only had a lumpectomy- to reduce your recurrence risk to the same breast. That is for your own benefit. You are young which means your risk for cancer recurrence will be quite significant- so you want to reduce it as much as possible.