“Will a heating pad help tennis elbow?”

Sorry your elbow is hurting. Tennis elbow is an irritation of your forearm muscles or small tears of tendons off the bone. It is very common even if you don't play tennis. Almost everything works to make the elbow better but it takes a long time to really heal itself. The heating pad will give you temporary relief.

Heating will usually make tennis elbow worse.

Ice is better after activities, but heat can be helpful prior. Stretching daily is also very beneficial.

It is usually good for stretching your elbow muscles at the beginning of the day. Try running hot water from the shower on your elbow as you are stretching your wrist downward (towards the palm). At the end of your day or after exercising, massage your elbow where it hurts with an ice cube for about 5 minutes. I’ve found that tennis elbow syndrome is often associated with sub-clinical carpal tunnel and/or cubital tunnel syndromes. Try the the elbow and wrist stretches from my video:

https://www.romanomd.com/videos-orthopaedic-surgeons-oak-park-river-forest-elmhurst.html

Good question! A rule of thumb: "Warm-up and then cool down." Warm or heat on the elbow or any body part is just fine to get it going before you use it. This dilates the blood vessels and gets blood to the sight allowing you to start using it. After using it, working out or after a long day of use, cool it down or ice it. For tennis elbow, a heating pad (not too hot) for 10 minutes is fine and then for icing, take small paper cup (Dixie cup), fill it with water, put it in the freezer. When frozen, take it out and peel back the edges and do an ice massage on the sore part of the elbow for 10 minutes, that is the best way to ice for tennis elbow. Hope this helps!