What could lumps on the back left side of your skull be that are painful to touch and seem hard but squishy because they have multiplied grown one is really LONG so what they?

It is difficult to determine the exact cause of these lumps without a proper medical evaluation. I recommend consulting a healthcare professional to get an accurate diagnosis and appropriate treatment. Here are a few possible causes based on the symptoms you described:

1. Swollen Lymph Nodes: Enlarged lymph nodes, particularly those on the back of the head, can sometimes be hard but squishy and may feel painful to the touch. Swollen lymph nodes are often a sign of an infection or underlying medical condition.

2. Sebaceous Cysts: These are noncancerous growths that develop from the sebaceous glands in the skin. They can occur on the scalp and feel firm or doughy to the touch. Sebaceous cysts can sometimes become painful if they get infected.

3. Lipoma: Lipomas are benign fatty tumors that can grow anywhere on the body, including the scalp. They are typically soft and movable and can be painful if they press on nerves or blood vessels.

4. Pilar Cysts: These are noncancerous cysts that form around a hair follicle. Pilar cysts can occur on the scalp and may feel firm or hard to the touch. They can be painful if they become infected.

5. Other Causes: In some cases, lumps on the back of the skull can also be caused by conditions such as skin infections, abscesses, or even bone growths.

It is important to seek medical attention if you are experiencing painful lumps on your head, especially if they are growing or persisting. A doctor will be able to properly examine and diagnose the lumps, and provide appropriate treatment.