In general, some states allow you to get a second opinion from another attorney while represented by another attorney. Contact a local attorney in your state and see what your options are.
I'm not certain I understand your question. I think you're saying that your lawyer sent you to a doctor who recommended that you have surgery and that for various reasons, you're not comfortable with the recommendation. I think it's always a good idea to listen to your gut feelings, if you are uncomfortable, speak to your present lawyer, get a second opinion about the surgery, get your questions answered and then, if you are still uncomfortable, find another attorney to represent you and another doctor to treat you.
This response does not constitute legal advice and does not create an attorney-client relationship. Due to the complexity and ever-changing nature of the law and to the limitations of this forum, this information may not be adequate for your specific situation.
It's hard to determine what they meant when they told you that they were using the surgeon's recommendation "for further care in settlement." It could be that the surgeon is not willing to perform surgery on a lien basis. (That's when a doctor or therapist provides care now, but agrees to wait for payment until after the case has resolved. The healthcare provider agrees to get paid from settlement proceeds.) Often, if the surgery is complex or costly, surgeons, hospitals, surgery centers, anesthesiologists, and all the other professionals involved in the surgery are not willing to do it on a lien. That may be the case here (although, again, their response is a bit vague).
Keep in mind that you do have a duty to mitigate your damages. So if you need the surgery, you have to make a reasonable effort to get it so as not to prolong your pain and suffering and to maximize your prospects for improvement after surgery. That means if you have healthcare insurance or other means of payment, you can't wait around for a settlement to get the surgery done. Also, you and your attorney have a duty to do a reasonable search for a surgeon who WILL do the surgery on a lien basis. (I'm assuming your attorney has already done so, but that may be a question you may want to ask.)
This response is based on limited information. It is not meant as and does not constitute legal advice and does not create an attorney-client relationship.
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