Welcome. There are several apps for Android that can read and write many of the chips currently available. Taginfo and NFC tools are the most commonly used, easy to find and free.
If either of these apps find a chip you will have the full support of this community and there are lawyers out there who would line up to prosecute whoever did this because it would be a ground-breaking case and there would be big money to be made.
However, be aware that this has never happened so far.
If the apps and X-rays and anything else fail to find a chip you will have to face that fact that your mind is playing tricks on you. This will have been compounded by internet trolls who enjoy scaring people with stories of malicious individuals chipping people for nefarious purposes. If this is the case, know that you are safe and your body is free of unwanted technology.
I edited this post to acknowledge that there are chips known as “LF” chips which would not be read by the Android apps. They would easily be seen by an Xray however. That said, I would not encourage you to spend money on organising an Xray to search for something I know is not there but it’s your money and your choice.
My basic point still stands: download an app and scan the area you believe the chip to be. When you don’t find the chip seek out a mental health care professional to show you how you have been persuaded (often by people with malicious intent) of the presence of the chip. I wish you every success in resolving this issue.