I keep having a muscle spasm on my hand where thumb is?

Muscle Spasm. You really need a proper evaluation by a medical doctor. Muscle spasm may be due to electrolyte imbalance (potassium, sodium problems), thyroid disease, or in your case to carpal tunnel syndrome, etc. The list is too long to list here, but you need a proper evaluation to get more of the background here (how long it has been going on, any trauma, etc) and possibly to order some lab tests.

Related Questions

I keep having a muscle spasm on my left hand right where the thumb muscle is? But I'm right handed. No injury?

It could be inflamed. You may want to see a doctor it could be inflammation of the joint. You should see your doctor. Ice and Ibuprofen will help.
Arthritis. If a person has arthritis or instability at the joint at the base of the thumb (basilar joint) the muscles hurt or spasm to protect the joint. It can occur on either hand or both.

Past year I've been having painful muscle spasms. I grab something and muscle between thumb/ index lock up. Bloodwork for thyroid, calcium, mag all ok?

Let try to help. Can you move your index finger or thumb when it locks up? If you cannot move either one of them, that's what we call trigger finger. Let me know please, I will tell you how to handle it.

Going to get thumb-size mole checked. I'm very tense person due to spasticity. Should I take muscle relaxer? Would that interfere w/med used to numb?

No NO. Exactly what do you mean by "muscle relaxer"? No you will not need a tranquilizer. No, it will not interfere with local anesthesia. You do not yet know if any procedure will be done. It will not hurt. Relax.