I think this is Earth (1972) by Marie C. Farca. ISFDb records only a single hardcover edition.
Andrew Ames (the narrator) and John Simms are away from Base Ship in their Duo Raft, investigating a planet. John miscalculates the planet's gravity and their planned orbit becomes an unplanned impact. The story follows their adventures on this uncharted planet.
life in an advanced society where people don't even walk, they float in chairs
"John, I can't move," Ames said, pushing the propellant lever steadily, then furiously. His chair, which had borne him all his adult life, sat crippled on the deck. He knew inertia in its worst sense.
a transistor malfunction was mentioned
Ames removed transistors from his chair control box and replaced the vital ones. He bent down and detached one lateral jet at a time and examined each for any impediment to the air flow.
their muscles are thus atrophied.
He even let himself down to the deck. His unused legs formed a cushion beneath him.
They can only speak very quietly as their voices are transmitted. There is no notion of privacy, people live in small rooms with transparent walls, others can freely move through their "apartment."
He couldn't remember his room number. Damn the impure air! Room. That was a joke. First city complex consisted of transparent dividers, and each cubicle consisted of a personalized supply of pellets, scans and computers to bring information, scans and computers to take information, scans to bring amusement or social contacts. People floated as freely within as air flowed here inside the dome. The environment was programmed, the meeting of every need was programmed. But nobody ever touched anybody else.
people are cloned, not born, and there are many cloned siblings of a person.
Ames had told Ecol, "There are already activated clones of me. I am this but I am also ten and twenty."
"I do not understand."
"I mean back home there is a ten-year-old version of my body and a twenty-year-old version. The ten-year-old version is being exposed to a different environment from mine.
The protagonist has an accident in a spacecraft
Ominous mountain chains snarled. Strictly visually. If they could just clear those. At least the sharp and youthful worst of them. Concave markings on valley floors. Planet pitted by a big careless hand which had moved recklessly in its clawing. Hang up there, Raft. Clear one more jagged-edged pock mark. Gliding sideways and downward. Retros! Retros! Hold! Fight the awful pull. The planet must know it's going to win. Make it respect you. Make it draw you down with some sort of grace. Demand your own dignity of it. A convex form ahead just where they would be least able to afford it. All those pits and just ahead there had to be something which bubbled. Overfly it! Good! Good! The Raft hit. Abrupt, deep impact.
becomes stranded on a primitive world where people live in a dome;
We have an obscuring translucent mound to our backs. It extends perhaps a thousand, maybe more, upward and countless kayems side to side. I cannot see to its most distant point straight behind us. It seems to cover... it rises as though there might be a mountain under it. This might suggest an air flow beneath the dome, a colder air at the high section of the dome dancing in step with rising warmer air where the dome is slung low. There might be a viable atmosphere under there. Three is a modest-sized river exiting from the dome.
learns to walk, work, love and to live as an earlier human before being rescued.
"You gift yourself well," Hunter would call from time to time, as he sat shaping a pointed wooden spear. "Stay and walk some more. The sooner you can walk, the sooner you can leave the dome and accomplish the things we talked about."
I only remember one name, 'Lady', which the love interest of the main character was called.
"Don't go, Lady. Stay with me," he said with anxiety.
"Why?"
He did not know why. "Because your touch is unreal. Lady! Lady!" Pleasure had its inverse. "Lady, I ache! Lady! ... Lady! ... Lady!"
One device in the story is a "cloning bag", whereby a single cell of a person can be deposited and a baby clone will be gestated and be able to crawl out when fully formed.
John suffers a catastrophic suit failure and massive decompression, and Ames must salvage what he can.
He put a clone bag into the gape in front of the suit. With his other hand, he removed a scope and activated it, hooking it on the helmet so that it hung before his right eye. He removed a milli-knife from the side of the clone bag. Using the knife and viewing through the scope, he searched the ruins of the body for an undamaged cell. He found three in close succession and deftly took the middle one and dropped it into the chemicals-laden clone bag, which sealed itself. As he marked the bag, Ames wished he were in it. The normal pressure must be blissful. He remembered what his own face had looked like and refrained from lowering the dark visor again. Using a second clone bag and its tools, Ames repeated the action, this time using a slightly larger cell. Then he reached inside his own useless suit, methodically cut into his own thigh, removed a healthy cell, and popped it into the third self-seal bag. He marked it R1403.
